JACKSON, Miss. — Longtime Republican Sen. Thad Cochran of Mississippi, chairman of the Senate Appropriations Committee, told The Associated Press on Monday that he will resign April 1 because of health problems.

Cochran, who turned 80 in December, stayed home for a month last fall with urinary tract infections, returning to Washington in October to give Republicans the majority they needed to pass a budget plan.

“I regret my health has become an ongoing challenge,” Cochran said in a statement. “I intend to fulfill my responsibilities and commitments to the people of Mississippi and the Senate, through the completion of the 2018 appropriations cycle, after which I will formally retire from the U.S. Senate.”

He was first elected to the Senate in 1978 after serving six years in the House.

“It has been a great honor to serve the people of Mississippi and our country. I’ve done my best to make decisions in the best interests of our nation, and my beloved state,” Cochran said.

Republican Gov. Phil Bryant will appoint a temporary replacement. Then a special election will be held to fill the rest of the term, through January 2021.

Senate Majority Leader Mitch McConnell of Kentucky praised Cochran.