Trump hinted at moving to fire Powell, whose term does not expire until 2026.
The Republican president's broadside comes a day after Powell said in a speech that Trump's broad-based tariffs have left the Federal Reserve seeking "greater clarity" on the impact of policy changes in areas such as immigration, taxation, regulation and tariffs before making the move on interest rates.
"Oil prices are down, groceries (even eggs!) are down, and the USA is getting RICH ON TARIFFS," Trump said in a social media post on Thursday.
Referring to the European Central Bank, he said Powell "should have lowered Interest Rates, like the ECB, long ago, but he should certainly lower them now. Powell's termination cannot come fast enough!"
The European Central Bank on Thursday lowered its key interest rate from 2.5 per cent to 2.25 per cent.
Powell was initially nominated by Trump in 2017, and he was appointed to another four-year term by President Joe Biden in 2022.
At a November news conference, Powell indicated he would not step down if Trump asked him to resign.
He has also said the removal or demotion of top Fed officials was "not permitted under the law".
Powell started Trump's second term in a relatively secure spot with a low unemployment rate and inflation progressing closer to the Fed's two per cent target, conditions that could have spared the US central banker from the president's vitriol.
But Trump's aggressive and haphazard tariffs have increased the threat of a recession with both higher inflationary pressures and slower growth, putting Powell in a tough spot.
With the economy weakening because of Trump's choices, the president appears to be looking to pin the blame on Powell.
Powell, in his remarks at the Economic Club of Chicago on Wednesday, said the Fed would base its decisions solely on what was best for all Americans.
"We're never going to be influenced by any political pressure," Powell said.
"Our independence is a matter of law. We're not removable except for cause.
"Congress could change that law, but I don't think there's any danger of that. Fed independence has pretty broad support across both political parties and in both sides of the Hill."
