Mitch McConnell, the powerful Republican lawmaker who was instrumental in steering the current US shift to the political right but had a tempestuous relationship with Donald Trump, announced Thursday he will step down from the Senate.

At 83 and in increasingly unsteady health, McConnell's announcement that he will not seek reelection when his term expires was not a big surprise. But after serving seven terms and earning a reputation as Congress's ruthless, master tactician, the Kentucky senator's retirement will draw the curtain on a political era.

"My current term in the Senate will be my last," he said.