Global central banks have issued an extraordinary joint statement offering “full solidarity” to the US Federal Reserve chair, Jerome Powell, in the face of the latest threat to his independence from Donald Trump’s White House.

“The independence of central banks is a cornerstone of price, financial and economic stability in the interest of the citizens that we serve. It is therefore critical to preserve that independence, with full respect for the rule of law and democratic accountability,” the statement said.

It was signed by nine central bank governors including the Bank of England governor, Andrew Bailey, and the chair of the European Central Bank, Christine Lagarde. It was coordinated by the Basel-based Bank for International Settlements, which added its chair and general manager to the signatories.

Other signatories to the unprecedented statement include the central bank governors of Australia, Sweden, Denmark, Switzerland, Brazil, South Korea and Canada. More names are expected to be added later on Tuesday.

They pay testament to Powell’s “integrity” and “unwavering commitment to the public interest”, calling him a “respected colleague who is held in the highest regard by all who have worked with him”.

Trump has repeatedly criticised Powell, whom he appointed in 2018, for failing to cut interest rates fast enough.

But the clash between the two men took a dramatic turn earlier this week when Powell issued a strongly worded video statement, saying he was being prosecuted by the US Department of Justice.

He called the move “unprecedented action [that] should be seen in the broader context of the administration’s threats and ongoing pressure” over monetary policy.

He said he had been singled out because the Fed’s policymaking board had set interest rates “based on our best assessment of what will serve the public, rather than following the preferences of the president”.

Trump has moved to distance himself from the investigation, however, claiming he was unaware of it. “I don’t know anything about it,” he told NBC News.

The Fed has cut interest rates three times since last summer, but Trump has urged it to move faster, and personally attacked Powell as a “numbskull”.

The Department of Justice has said the case relates to “abuse of taxpayer dollars” – assumed to be in relation to costly renovations at the Fed’s headquarters.

Powell is due to step down as chair of the Fed board in May, and Trump is expected to announce his successor in the coming weeks.

The former Fed chairs Alan Greenspan, Ben Bernanke and Janet Yellen had already condemned the threat to Powell on Monday, saying the move could have “highly negative consequences”.

“This is how monetary policy is made in emerging markets with weak institutions, with highly negative consequences for inflation and the functioning of their economies more broadly,” their statement said.