The world’s most powerful central bankers have voiced their support for Jerome Powell, warning of the critical need to preserve the independence of their institutions after the Trump administration launched a criminal investigation into the chairman of the US Federal Reserve.

In an unprecedented joint statement, 11 global central bank chiefs, including Andrew Bailey of the Bank of England and Christine Lagarde of the European Central Bank, said they stood “in full solidarity with the Federal Reserve system and its chairman”.

They said: “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.”

• Inside Trump’s war on the Fed chairman Jerome Powell

The statement comes after Powell revealed he was the subject of a criminal investigation by the US Department of Justice over his testimony to Congress about the renovation of a Fed building. It is the latest escalation in attacks on Powell, who has been lambasted by President Trump for being too slow to cut interest rates.

“Chair Powell has served with integrity, focused on his mandate and an unwavering commitment to the public interest,” the joint statement said. “To us, he is a respected colleague who is held in the highest regard by all who have worked with him.” Signatories also included central bank heads from Canada, Australia, Sweden and France.

The warning from global central bank chiefs underlines the importance of the Fed’s credibility for financial markets and governments around the world. The market reaction to the investigation has been muted as investors have taken some comfort in the defence of the Fed from some US lawmakers and press reports that Scott Bessent, the US treasury secretary, does not support the investigation into Powell.

• Former heads of US Fed condemn criminal inquiry into Jerome Powell

Jamie Dimon, chief executive of JP Morgan, America’s biggest bank, said he had “great respect” ⁠for Powell and was a strong supporter of Fed independence.

“Anything [that] chips away at that is probably not a great idea,” Dimon said on a call to accompany JP Morgan’s fourth-quarter results. “And in my view, it will have the reverse consequence. It will raise inflation expectations and probably increase rates over time.”

Janet Yellen, a former head of the US central bank, has called the investigation the most serious violation of the Fed’s independence from political interference in recent times.

“If you can bring charges for no reason whatsoever against your enemies, we’re no longer living in a society governed by the rule of law. That’s the end of Fed independence,” Yellen said.

A group of economists and former US central bankers, including the former Fed chiefs Ben Bernanke and Alan Greenspan, said on Monday that the case was “an unprecedented attempt to use prosecutorial attacks to undermine that independence”.

They said: “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. It has no place in the United States whose greatest strength is the rule of law, which is at the foundation of our economic success.”

Powell’s second term at the Fed is due to end in May and the White House is in the process of announcing his successor. Powell can remain as a member of the Fed’s governing board until 2028.