By Jonnelle Marte

(Reuters) – U.S. Federal Reserve Chair Jerome Powell faced heated questions on Tuesday from senators criticizing the central bank’s trading guidelines, financial regulation and diversity efforts.

The U.S. Senate Banking Committee heard Powell defend the central bank, and promised to make improvements where necessary.

This is a blow for the image of central bank,” said Senator Raphael Warnock from Georgia. Powell answered his question about the steps that he was taking to safeguard the Fed’s independence.

After some critics, Powell asked about the steps he was taking to protect the “impartiality” of the Fed.

Powell earlier this month directed a Fed review on its ethics rules. He also stated that the central banking is examining trades made by Fed regional presidents in order to ensure they are legal and comply with the current ethics guidelines.

Powell replied to a query, saying that even if these trades appear to have been in compliance with the existing rules that does not mean that the practice and disclosure need to be improved. This is where we will step up and fix it.

In February, the Fed’s chief will expire. Democratic Senator Elizabeth Warren of Massachusetts also called him “dangerous” and threatened to vote against his recall.

“Renominating you means gambling that … a Republican chair who has regularly voted to deregulate Wall Street won’t drive this economy over a financial cliff again,” said Warren, a long-time critic of the Fed’s oversight of Wall Street. It’s not a risk that I think it’s worth taking.

Although the White House is yet to announce a decision about whether Powell will be reappointed or if it will choose another candidate,