US President Donald Trump on Friday again floated the idea of firing Jerome Powell, the Federal Reserve chair he has long attacked over interest rates he wants lowered.

"I don't know why the Board doesn't override (Powell)," Trump wrote in a lengthy post on Truth Social criticising Fed policy. "Maybe, just maybe, I'll have to change my mind about firing him? But regardless, his Term ends shortly."

Trump added: "I fully understand that my strong criticism of him makes it more difficult for him to do what he should be doing, lowering Rates, but I've tried it all different ways."

Fed policymakers have long been seen as insulated from presidential dismissal for reasons other than malfeasance or misconduct, but Trump has threatened to test that legal premise with long-running threats to fire Powell.

Just last week, though, Trump set aside the idea. "I'm not going to fire him," he said at the White House on June 12.

The Fed held rates steady on Wednesday and forecast slower growth as well as higher unemployment and inflation by year's end.

Elected partly on voters' belief that he could contain high inflation, the Republican US president has imposed tariff hikes in office. Powell, echoing an academic consensus, has said some of those tariff hikes will be paid for in higher consumer prices.

Powell's term ends in May 2026, and Trump is expected to nominate a successor in the coming months.

A Supreme Court ruling in May eased concerns that Trump could fire Powell as the justices called the Fed "a uniquely structured, quasi-private entity." (Reuters)