WASHINGTON (Reuters) - U.S. acting Attorney General Matthew Whitaker will appear before the House of Representatives Judiciary Committee in January, when a new Democratic majority expects to begin ramping up House oversight of the Trump administration.

FILE PHOTO: Acting U.S. Attorney General Matthew Whitaker speaks at the Joint Terrorism Task Force office in New York, New York, U.S., November 21, 2018. REUTERS/Carlo Allegri

Two Democratic lawmakers including Representative Jerrold Nadler, incoming chairman of the House judiciary panel, said in a joint statement on Friday that Whitaker committed to appear before the committee during a phone conversation.

Whitaker, whom President Donald Trump appointed without Senate confirmation this month after ousting Attorney General Jeff Sessions, has raised alarms among Democrats who fear he could endanger Special Counsel Robert Mueller’s probe into Russian meddling in the 2016 presidential election and possible collusion with the Trump campaign.

U.S. President Donald Trump has repeatedly denounced the Mueller investigation as a “witch hunt” and appealed to then-Attorney General Sessions to end the probe on Aug 1.

As a Trump loyalist, Democrats say, Whitaker could fire Mueller, starve the Russia investigation of funding or prevent a special counsel report from being made public.

But Nadler and Representative Elijah Cummings, incoming chairman of the House Oversight Committee, said in their statement that Whitaker pledged to operate according to established Justice Department practice.

“Acting Attorney General Whitaker committed to appear before the House Judiciary Committee in January at a mutually agreeable date,” Nadler and Cummings said.

“The acting attorney general affirmed that he was and will continue to follow all of the regulations, policies and procedures of the Department of Justice, including with regards to the Special Counsel investigation,” they added.

Justice Department officials were not immediately available for comment.

Democrats and other critics say Whitaker’s appointment could represent an illegal attempt to take oversight of Mueller from Deputy Attorney General Rod Rosenstein, who had supported the special counsel after Sessions recused himself from the probe.

The U.S. Constitution requires Senate confirmation for principal government officers.

Whitaker was also the subject of a 2017 fraud query from the Federal Trade Commission over his involvement with World Patent Marketing, a company accused by the government of bilking millions of dollars from consumers.