The list includes St. Louis Fed President James Bullard and Marc Sumerlin, a former economic adviser to President George W. Bush, the source said, confirming an earlier report by the Wall Street Journal that said there were now about 10 contenders for the spot. President Donald Trump last week said he had narrowed the list to four.

National Economic Council director Kevin Hassett and former Fed governor Kevin Warsh remain under consideration, along with current Fed governor Christopher Waller, the source told Reuters.

Trump has pressured Powell all year to cut interest rates, building on his past comments critical of the Fed chief that emerged during his first term as president shortly after he elevated Powell to the Fed chair role. Powell's term ends in May. Critics have said the president should let Fed chair Powell complete his term without interference.

Hassett, Warsh and Waller have all signaled support for lower rates, which Trump had indicated would be a requirement for the job.

Bullard, who left the St. Louis Fed last year to be dean of Purdue University's business school, was Waller's boss before Trump plucked the regional Fed's research director from under Bullard to serve on the Fed Board. As recently as May he said he thought the Fed would probably be able to cut rates by September.

The recent monetary policy views of Sumerlin were not immediately clear.

It was also not clear what a broader list of candidates would mean for the timing of an appointment.

The president moved quickly to name an ally to the Fed Board this week after Fed Governor Adriana Kugler, a Biden appointee who did not support rate cuts, unexpectedly resigned as of the end of this week. Council of Economic Advisers Stephen Miran will serve out the remaining months of Kugler's term, which ends on January 31.

Trump has indicated a search continues for someone who could fill the Fed Board role for a 14-year term beginning February 1.

(This story has been corrected to fix the spelling of Reuters in paragraph 1)