President Donald Trump on Tuesday called preparations to impeach him in US Congress "absolutely ridiculous" and said they were causing "tremendous anger."

Trump, speaking as he boarded Marine One at the White House for a trip to Texas, called his likely impeachment in the House of Representatives on Wednesday a "continuation of the greatest witch hunt in the history of politics."

In his first remarks to reporters since December 8, the embattled president did not answer a question about whether he would resign.

Trump would become the first U.S. president to be impeached twice if the House of Representatives votes in favor of impeachment on Wednesday.