US stocks and the dollar plunged again as President Donald Trump intensified his attacks on US central bank boss calling him "a major loser" for not lowering interest rates.

In a social media post, Trump called on Federal Reserve chair Jerome Powell to cut interest rates "pre-emptively" to help boost the economy, saying Powell had been consistently too slow to respond to economic developments.

"There can be a SLOWING of the economy unless Mr. Too Late, a major loser, lowers interest rates, NOW," he wrote.

Trump's criticism of Powell's handling of the US economy comes as his own plans for tariffs have driven a stock market sell-off and raised fears of economic recession.

The president's intensifying clash with Powell, whom he named to lead the Fed during his first term, has added to the market turmoil.

The S&P 500, which tracks 500 of the biggest US companies, fell roughly 2.4% on Monday. It has lost roughly 12% of its value since the start of the year.

The Dow Jones Industrial Average dropped 2.5% and has dropped about 10% so far this year, while the Nasdaq fell more than 2.5% and is down roughly 18% since January.

Though the dollar and US government bonds are typically considered safe assets in times of market turmoil, they have not escaped the recent turbulence.

The dollar index - which measures the strength of the dollar against a set of currencies including the Euro - on Monday fell to its lowest level since 2022.

Interest rates on US government debt also rose, as investors demanded higher returns for holding Treasuries.

Trump's criticism of Powell dates back to his first term in office, when he also reportedly discussed firing him. Since winning the election, he has urged Powell to lower borrowing costs.

The latest criticism follows Powell's warnings that Trump's import taxes were likely to drive up prices and slow the economy.

Trump last week called publicly for Powell to be fired, writing on social media on Thursday: "Powell's termination cannot come fast enough,".

Such a move would be controversial - and legally questionable - given a tradition of independence at the bank.

Powell last year told reporters he did not believe the president had the legal authority to remove him.

But one of Trump's top economic advisers confirmed that officials were studying the option on Friday, when the stock market in the US was closed for trading. (BBC)

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