At least 150 people are also injured, officials say. While the cause of the deaths is unknown, authorities report cases of people suffering from ‘cardiac arrest.’

The United States government is ready to provide South Korea with “any support it needs” after the deadly incident in Seoul’s Itaewon neighborhood Saturday night, White House national security adviser Jake Sullivan said on Twitter. 

“The reports out of Seoul are heartbreaking. We are thinking about all those who lost loved ones and hoping for a quick recovery for those injured. The United States stands ready to provide the Republic of Korea with any support it needs,” Sullivan wrote. 

The death toll has reached at least 146 from the Halloween incident in Seoul’s Itaewon neighborhood Saturday night, according to the Yongsan Fire Department chief.

At least 150 others were injured in the incident, the chief added.

The causes of death have not yet been reported, but Yonhap News Agency reported that dozens of people suffered from “cardiac arrest” from the incident, citing fire officials.

With local hospitals treating dozens of injured people from the Seoul Halloween emergency, the death toll will likely increase, a local health official said.

The cause of injuries and deaths in the incident has not been officially confirmed, added Choi Jae-won, the head of Yongsan Health Center.

Local fire officials said the emergency was not due to a gas leak or a fire in the popular nightclub district, but that they started receiving reports of people “buried” in the crowds there around 10:24 p.m. local time (9:24 a.m. ET) Saturday.

CNN’s Will Ripley reported that even before the chaos broke out, Halloween partygoers were packed so tightly in the narrow streets that it was difficult to move around.

Officials said they are still investigating the exact cause of the incident that killed at least 120 people in Seoul’s Itaewon neighborhood Saturday night.

Choi Seong-bum, chief of the Yonsan Fire Department, said there was no gas leak nor fire in the popular nightclub district, but that they received reports of people “buried” in crowds starting around 10:24 p.m. local time (9:24 a.m. ET) Saturday night.

A witness described the chaotic scene to CNN, saying people were jammed and could not breathe.

“I saw the people going to the left side and I saw the person getting to the opposite side. “The person in the middle got jammed, so they had no way to communicate, they could not breathe,” Song Sehyun told CNN.

Emergency workers formed a long line of waiting stretchers after over 100 people were killed during Halloween festivities in Seoul’s popular nightclub district.

Authorities have released few details about the exact cause of the incident, but Yonhap News Agency reported dozens of people suffered from “cardiac arrest” and had trouble breathing.

CNN’s Will Ripley said that when he arrived in the Itaewon neighborhood, there were streams of people walking through the streets, crying and talking on the phone, still wearing costumes from what was intended as a celebration.

While there were paramedics with ambulances still looking for anyone who needed to go the hospital, Ripley reported that the long line of stretchers forming on the street would be used to take bodies from the scene.

Some background: People fly into Seoul from all over Asia to celebrate Halloween in Itaewon, Ripley noted. Hotels and ticketed events in the neighborhood were booked solid ahead of this weekend’s festivities, he said.

The death toll has reached at least 120 from the Halloween incident in Seoul’s Itaewon neighborhood Saturday night, according to the Yongsan Fire Department chief.

At least 100 others were injured in the incident, the chief added.

The causes of death have not yet been reported but Yonhap News Agency reported that dozens of people suffered from “cardiac arrest” from the incident, attributing fire officials.

South Korean President Yoon Suk Yeol dispatched a disaster medical assistance team to the Halloween incident in Seoul’s Itaewon neighborhood, according to the presidential office.

The president also ordered authorities to secure emergency beds in hospitals nearby and to implement swift rescue operations and treatment, Presidential spokesman Lee Jae-myung said in a briefing.

At least 59 people were killed in the Halloween incident in Seoul’s Itaewon neighborhood Saturday night, according to the Yongsan Fire Department chief.

At least 150 others were also injured, the chief added. 

The cause of the deaths was not immediately provided, but the chief said many people fell during the Halloween festivities, resulting in casualties.

Yonhap News Agency reported dozens of people suffered from “cardiac arrest,” according to fire authorities, and at least 81 people told emergency officials they had “difficulty breathing.”

A total of 848 emergency forces have been dispatched, including 364 firefighters and 400 police officials, according to the chief.

Police have closed off the area in the neighborhood, and social media videos are showing people lying in the streets.

Authorities have not yet provided exact details on the cause of the incident or conditions of those injured.