Jerome Powell is facing a criminal investigation over his testimony to Congress about the renovation of the Federal Reserve buildings

US President Donald Trump's administration is using a criminal investigation as "intimidation" to pressure the Federal Reserve over its monetary policy, Fed Chair Jerome Powell said on Monday.

The US president has long criticized Powell for refusing to make bigger interest-rate cuts, as well as over the $2.5 billion in reconstruction costs of the institution's historical buildings, which Trump described as excessive.

The inquiry into whether Powell lied to Congress about the scope and costs of the Fed buildings renovation was approved in November by US Attorney for the District of Columbia Jeanine Pirro, a longtime Trump ally, the New York Times wrote on Sunday, citing insiders.

"This new threat is not about my testimony [to Congress] last June or about the renovation of the Federal Reserve buildings," Powell said in a video address published on X, arguing that the reasons given by the Department of Justice for the probe "are pretexts."

The US president has denied any links to the investigation.

"I don't know anything about it, but he's certainly not very good at the Fed, and he's not very good at building buildings," he told NBC news on Sunday.

Trump had long threatened to replace Powell, arguing that the Fed's refusal to cut rates faster was slowing down the US economy.

Powell has maintained that he has always done his job "without political fear or favor," no matter the administration, and has vowed to continue to do so. He has served as Fed chair since 2018, nominated for the position by Trump during his first presidential term, and renominated by former President Joe Biden in 2022.