Longtime Iowa Sen. Chuck Grassley is running for reelection

Washington (CNN)Iowa Republican Sen. Chuck Grassley announced on Friday that he will run for reelection next year.

“It’s 4 a.m. in Iowa so I’m running. I do that 6 days a week. Before I start the day I want you to know what Barbara and I have decided,” Grassley, who is 88 and was first elected to the US Senate in 1980, wrote on Twitter. “I’m running for re-election—a lot more to do, for Iowa. We ask and will work for your support. Will you join us?”

This story is breaking and will be updated.