Explosions rock Kyiv and Odesa overnight after Kremlin incident.

Ukraine, which typically practices a policy of deliberate ambiguity over whether it has been responsible for attacks inside Russia, denied any responsibility for the drones on Wednesday, with President Volodymyr Zelensky saying Moscow had manufactured the incident to stir up public support.

Mr. Zelensky was in the midst of a rare trip outside Ukraine, arriving in the Netherlands late Wednesday after spending the day meeting with the leaders of Nordic nations in Finland. While in the Netherlands, he was expected to speak at The Hague, visit the International Criminal Court and meet with Prime Minister Mark Rutte in Amsterdam on Thursday, according to Dutch media reports.

Mr. Zelensky has long urged that Mr. Putin and the officials who helped bring war to Ukraine be held accountable by international law. He and other Ukrainian officials have proposed that European leaders set up a tribunal for that purpose, one that could work alongside the International Criminal Court but bypass its long, onerous prosecution process. Mr. Zelensky referred to such a tribunal on Wednesday.

“We didn’t attack Putin,” he said. And as for the Russian leader’s fate, he said, “We leave it to the tribunal.”

Ukraine’s preparations for an expected counteroffensive have been underway for weeks. Mykhailo Podolyak, an adviser to Mr. Zelensky, suggested on Wednesday that Russia could have staged the drone attack to justify launching a “large-scale terrorist provocation” against Ukraine in the coming days.

Mr. Putin is set to preside over a military parade on Tuesday, Russia’s main patriotic holiday known as Victory Day — the celebration of the Soviet Union’s World War II victory over Nazi Germany.

The air raid sirens that had wailed in Kyiv three of the previous six nights rang out again early on Thursday. Three loud booms were heard about 2:30 a.m. It was not known whether the sounds were air defense weapons exploding in the sky or missiles hitting targets.

Marc Santora, Andrew E. Kramer and Johanna Lemola contributed reporting.

Mr. Prokudin said the measure was needed because of unspecified threats posed by Russian forces and to facilitate the unimpeded work of Ukrainian law enforcement and military.

“During these 58 hours, it is forbidden to move and be on the streets of the city,” he said.

The curfew order was among the most sweeping Ukraine has put in place since similar edicts were issued in Kyiv at the start of the invasion. The Ukrainian military ordered people off the streets for days as they worked to find spies and saboteurs and beat back the Russian advance on the capital.

Image

Kherson has come under sustained and withering Russian bombardment since the fall, when Ukrainian forces drove the Russian troops out of the port city and the surrounding area west of the Dnipro River. It was a significant victory for Ukraine, because the city had been the only regional capital Russia had managed to capture since Moscow launched its full-scale invasion in February of last year. But the Russian forces decamped just across the river, and from there have relentlessly shelled civilian areas.

Russian units have also been building defensive positions for months. In recent weeks, the Ukrainian military has warned that Russian occupation authorities in the Kherson region have been preparing to evacuate civilians from the territory it still controls there ahead of an expected Ukrainian counteroffensive.

Ukrainian officials said the strike on the mall took place around 11 a.m. and those injured and killed included workers and shoppers at the complex. It was part of a broader assault by Russian forces in Kherson over the past day, which saw at least 106 attacks from Russian heavy artillery, rocket launchers, tanks, drones and aircraft, according to local Ukrainian authorities.

The influential Russian military blogger Rybar claimed that Russian forces were battling Ukrainians as they sought to gain control over the islands in the sprawling estuary that now divides the two armies. The claims could not be independently verified, though there were also unconfirmed reports last month that small groups of Ukrainian soldiers had grabbed marshy islands in the river.

The mouth of the Dnipro River, which flows into the Black Sea, forms a 350-square-kilometer basin. It is 1.2 kilometers wide and with the bridges over the waterway destroyed, it is exceedingly difficult for either army to cross. South of Kherson, the river then divides into a maze of branches, divided by strips of land large enough for settlements to be built.

“We are preparing several important, potent steps to further consolidate partners and provide more energy to creating a tribunal for the crime of Russian aggression,” he said in a nightly address over the weekend. Russia, he said, “must fully answer for everything it has done.”

The proposed tribunal would run parallel to cases pursued by the International Criminal Court, which last month issued an arrest warrant for Mr. Putin and another official on war crimes charges for their involvement in the forced removal of children from Ukraine. But the crime of aggression, the legal doctrine that would most directly hold Russian leaders to account for the invasion, cannot be pursued against Russia by the I.C.C. because it lacks jurisdiction.

First recognized as an international crime in the Nuremberg Trials of prominent Nazis, a crime of aggression is defined as being perpetrated by a leader — “a person in a position effectively to exercise control over or to direct the political or military action of a state” — by engaging in “the use of armed force by a state against the sovereignty, territorial integrity or political independence of another state” in violation of the United Nations Charter.

Beth Van Schaack, the State Department’s ambassador at large for global criminal justice, said last month in a hearing before the Senate Judiciary Committee that a tribunal would mark “the first prosecutions of the crime of aggression in the modern era.”

In March, the European Union said it was setting up a center for prosecuting crime of aggression cases in The Hague to coordinate the collection of evidence and investigation into Russia’s aggression in Ukraine.

Russian forces also attacked the southern port city of Odesa with at least 15 drones, Ukraine’s southern military command said. The Ukrainians shot down 12 but three other drones got through the air defense network and crashed into dorms. There were no reports of casualties, the Ukrainian military said.

There were also reports of widespread bombardments in towns and cities closer to the sprawling front line in eastern and southern Ukraine and the damage was being assessed early Thursday morning. The overnight aerial bombardment came after a day of ferocious Russian shelling in and around the southern port city of Kherson that killed at least 21 civilians, President Volodymyr Zelensky said in statement.

Mr. Zelensky is scheduled to speak at The Hague as part of a visit to the Netherlands. It is the home of the International Criminal Court, which issued an arrest warrant accusing Russia’s president, Vladimir V. Putin, of unlawfully deporting Ukrainian children to Russia.

Video

Russia said that it downed the drones, that the damage from the explosions was minimal and that no one was injured. Mr. Bendett said that it was unclear from the videos whether the objects exploded as planned or were shot down by air defenses. He added that one of them appeared to be “sizable.”

Mr. Bendett said a drone attack by Ukraine would have been undertaken primarily for psychological effect, to show that even the Kremlin was not safe.

Footage of the aftermath of the attacks was published by a local Moscow Telegram channel. Later, TV Centre, a Russian news outlet, posted videos of both explosions, including the moments of detonation above the Kremlin.

While there have been drone attacks in Russian territory since Moscow invaded Ukraine more than a year ago, a strike on the Kremlin by Ukraine would be a significant escalation. Current and former U.S. officials told The Times that the explosions could be a false flag operation carried out by Russia, but that it was too soon to know. Officials said U.S. intelligence agencies were still trying to determine what happened.

The Russian presidential press service said it regarded the explosions as a “planned terrorist act and an attempt on the life” of President Vladimir V. Putin. In a statement, a Ukrainian presidential adviser, Mykhailo Podolyak, strongly denied responsibility for the explosions, saying that Ukraine does “not attack targets on the territory of the Russian Federation.”

The domed Kremlin structure houses the Russian Senate, as well as Mr. Putin’s office and an apartment he sometimes stays at, along with a ceremonial hall and the presidential library. Russian officials said that Mr. Putin was at his compound in a Moscow suburb about 20 miles from the Kremlin at the time of the explosions.

Flying drones over the Kremlin was already banned. Some 12 hours after video of the incident began spreading online, Moscow’s mayor announced on Telegram a ban on the launch of drones in the entire city.

Christina Kelso contributed video production.

Targeting infrastructure is a common military strategy for Russia. Over the winter, it sought to grind down Ukraine’s resistance by relentlessly assaulting the country’s power grid, upending civilian life and leaving millions without light, heat or water.

The vulnerability of underwater infrastructure became a particularly high-profile international concern last September, after explosions damaged two Nord Stream gas pipelines. Who exactly sabotaged the pipelines, which delivered Russian gas to Europe through the Baltic Sea, remains a mystery.

In an illustration of the risks facing Western information and security systems, just 400 or so undersea cables are responsible for transmitting more than 95 percent of the world’s internet traffic, Mr. Cattler noted. Those cables carry approximately $10 trillion in financial transactions each day, he said.

In response to heightened concerns, NATO established a center to coordinate security efforts for critical undersea infrastructure in February. Its leader, Lt. Gen. Hans-Werner Wiermann, said on Wednesday that the alliance was increasing the number of ships on patrol in the North and Baltic seas and was seeking to advance its undersea surveillance capabilities.

“The threat is real,” General Wiermann said, “and our reliance on this infrastructure is growing.”

“We have a country in the case of Russia that like a handful of other countries around the world is wrongfully detaining people, using them as political pawns, using them as leverage in a practice that is absolutely unacceptable and that we’re working both broadly to try to deter — but also at the same time to try to secure the release of those who are being unjustly detained,” Mr. Blinken said.

He added that the State Department was working on getting Russia to allow more consular visits with Mr. Gershkovich, who has had only one to date. The U.S. ambassador to Russia, Lynne M. Tracy, was able to meet with him on April 17.

Image

That visit came more than two weeks after he was detained, and followed repeated State Department calls for Russia to grant access. Consular access has been a consistent problem for Americans jailed in Russia. It was an issue with Brittney Griner, the basketball star who was detained shortly before Russia’s invasion of Ukraine in February of last year. She was freed in a prisoner swap in December.

Mr. Gershkovich is being held at Moscow’s infamous Lefortovo Prison, where inmates are held in isolation with rare visits by lawyers. He has appeared in public just once, to declare his innocence from inside a glass defendant’s cage in a courtroom on April 18. As expected, a judge denied his appeal to lift his pretrial detention and sent him back to Lefortovo.

At a United Nations event on Tuesday, the publisher of The Journal, Almar Latour, condemned the lack of consular access to Mr. Gershkovich, which he said had been “limited or delayed significantly.”

He said Mr. Gershkovich’s Russian lawyers had told Journal officials that he was receiving letters in jail.

“We have heard from them that Evan is thankful and is reading every letter he is getting,” Mr. Latour said.

At the press freedom event, David Ignatius, a Washington Post columnist, pressed Mr. Blinken on when the State Department might make a formal determination that a Russian journalist and Post contributor, Vladimir Kara-Murza, had been wrongfully imprisoned by Russia. Mr. Ignatius pointed out that Mr. Kara-Murza has been a permanent resident of the United States and that his wife and two children are U.S. citizens.

“I don’t want to put a time frame on it,” Mr. Blinken said. “Again, it’s something that we’re looking at constantly.”

Mr. Zelensky flatly denied that his country had carried out any such attack, saying Ukraine was focused on the fight on its own soil. “We’re defending our villages and cities,” he said.

Ukraine, Mr. Zelensky added, did not have the weapons to spare on such an attack and that it would be up to an eventual international tribunal to decide the Russian leader’s fate.

“We didn’t attack Putin,” he said. “We leave it to the tribunal.”

Mr. Zelensky was in Finland to meet with Finland’s president, Sauli Niinistö, and the leaders of Sweden, Norway, Denmark and Iceland to discuss topics including the war in Ukraine and the country’s bid to join NATO. For most of the first year of the war set off by Russia’s full-scale invasion in February 2022, Mr. Zelensky remained in Ukraine, but has made a handful of international trips since visiting the United States and Poland in December.

During a news conference with the Nordic leaders, Mr. Zelensky congratulated Finland for joining NATO, a process it completed last month, and wished Sweden a speedy completion to its bid to becoming NATO’s 32nd member nation.

“Ukraine can and must be the 33rd member,” he said. “We understand that at a time of aggression, it’s impossible to fulfill Ukraine’s accession to the alliance, but there is no obstacle to it.”

— Johanna Lemola

At roughly the same time that two drones were blowing up over the Kremlin in Moscow early Wednesday, the dark sky in Kyiv was being lit up by tracer fire and explosions thundered over the capital city as Ukrainian air defenses shot down the latest swarm of Russian attack drones.

The assault came on the same day the Ukrainian government noted that Kyiv’s population had almost returned to prewar levels. Officials said 3.6 million people now call Kyiv home, just short of the 3.9 million who lived there in February 2022, on the eve of Russia’s invasion.

Fourteen months of missile strikes and drone attacks, wailing sirens and booming air defenses have taken a toll on the city’s residents, even if it isn’t immediately apparent.

Anna Vinogradova, a choreographer, described the surreal juxtaposition of a recent attack: Rockets flew over her building as she lay in bed, listening to the birds sing outside her window and watching the sun come up.

Tuesday night was worse.

“We live in the city center, and last night was very loud,” she said. “I had a nightmare that the Russians entered our apartment, and I had to defend myself and kill them.”

She wasn’t sure what to expect when night fell again, as Russia reserved the right to retaliate.

“Today, I’m very tired, and I’m afraid the coming night will not be quiet,” she said. “Still, I’m following my usual routine: going to read and go to bed.”

When the Russians claimed to take out two Ukrainian drones above the Kremlin — around 2:30 a.m. local time on Wednesday, according to videos reviewed by The New York Times — Mr. Putin was at a sprawling compound about 20 miles to the west, his spokesman, Dmitri S. Peskov, told reporters. The compound is located in the elite suburb of Novo-Ogaryovo, along the Moscow River.

Mr. Putin travels frequently between the compound and the Kremlin in a lengthy motorcade. The rich residents of nearby compounds grumble quietly that the F.S.O. closes the road to other traffic while the president is in transit.

Russian media reports have suggested that, since the start of the coronavirus crisis, Mr. Putin has spent more time at the compound or at another rural spread northeast of Moscow, near Lake Valdai.

Image

While the vast grounds of the Kremlin contain the official presidential residence, it is more ceremonial than practical. Only recently did Mr. Putin publicly mention the existence of a private apartment that he claimed to use frequently — an unusual instance of him discussing his living arrangements.

“I have an apartment here, where I have been spending a lot of time lately, working, spending nights very often,” he told reporters when President Xi Jinping of China visited Moscow at the end of March.

Both his main office and his apartment are in the Senate Palace, a yellow domed structure that was visible in video footage showing what appears to be a drone exploding. The palace also contains Catherine Hall, a soaring blue and white circular reception room where Mr. Putin holds ceremonies, such as handing out state awards, and the dome itself covers the presidential library.

The Kremlin fortress holds various tourist attractions, like a museum of Czarist artifacts and jewels, and a medieval Russian Orthodox church where some czars are interred. It is also the central working venue of the presidential administration, although only the closest advisers to Mr. Putin spend time working near his office. The rest are in an office building outside the Kremlin walls.

Even when Mr. Putin appears to be in the Kremlin, he may not actually be there, according to a former F.S.O. captain who defected. The Russian president has established identical offices in multiple locations, all furnished and decorated the same in every detail, including matching desks and wall hangings, according to the former captain, Gleb Karakulov. Official reports have sometimes described him as being in one place when he was actually somewhere else, Mr. Karakulov told a London-based opposition news outlet, the Dossier Center, in early April.

The security measures around the Kremlin can obfuscate others’ locations, too. Since the advent of G.P.S. tracking, the signal in the vicinity of the fortress sometimes disappears or is teleported to an airport more than 20 miles outside Moscow. Taxi fares have been known to jump accordingly, as if the passenger traveled to the airport, not central Moscow.

Ivan Nechepurenko contributed reporting.

In April, the U.S. pledged $2.6 billion in aid, including $500 million in weapons and equipment from U.S. stockpiles and $2.1 billion it would use to buy more for Ukraine in the future.

Mr. Blinken said in the statement that the U.S. and its allies “will stand united with Ukraine, for as long as it takes.”

Drawdowns from U.S. stockpiles are not subject to congressional approval. But the announcement came a day after House Speaker Kevin McCarthy, a Republican, said in Israel, “I support aid for Ukraine.”

Mr. McCarthy had previously said that there would be no “blank check” for Ukraine, and some Republican members of Congress have called for curtailing American assistance to Kyiv. A spending bill passed in December allocated nearly $50 billion to Ukraine.

Whether the U.S. and its Western allies continue providing billions of dollars in military aid could depend on whether Ukraine’s counteroffensive is successful in reclaiming substantial territory from Russian forces, analysts say.