April 22 (UPI) -- Federal Reserve Chairman Jerome Powell's term is nearing its end and President Donald Trump is pushing for his replacement but an investigation into Powell may hold up the appointment of a new chair.

The Justice Department opened an investigation into Powell over the renovation of the Marriner S. Eccles Federal Reserve Board Building in Washington, D.C., which Trump claims has exceeded $3 billion. The renovation was not the beginning of Trump's feud with Powell but it has added to his effort to oust the chairman before the end of his term.

Powell's term as chairman of the Federal Reserve will end in May but he will remain on the Board of Governors until January 2028.

Typically when a Fed chair's term ends, they resign. However, Powell said he plans to stay put until a replacement is appointed.

At least one lawmaker, Sen. Thom Tillis, R-N.C., said he would not vote on a new chairman until the investigation into Powell is over.