President Donald Trump said in an interview broadcast this morning that his biggest mistake was naming former Alabama Sen. Jeff Sessions to be his attorney general.

According to Bloomberg, Trump said in a sit-down with NBC’s “Meet the Press” that it was his “biggest mistake.”

“I would say if I had one do-over, it would be, I would not have appointed Jeff Sessions to be attorney general,” Trump said.

It was the latest chapter in the tempestuous relationship between the President and the former Alabama senator, one of Trump’s earliest backers. Later Sessions, as attorney general, recused himself from supervising the Justice Department’s investigation of Russia interference in the 2016 election, leading to the appointment of Special Counsel Robert Mueller.

Trump repeatedly fired off angry tweets about Sessions for recusing himself for more than a year until the attorney general resigned in 2018.

Sessions is reportedly mulling over running for his old Senate seat, currently held by Doug Jones.