Embattled Treasury Secretary John Snow refused to comment on rumors of his possible successor, saying any discussion about how long he stays would be covered in a private talk with the president.

For his part, President Bush on Friday endorsed the job Snow is doing in the Cabinet.

"The president said earlier today that Secretary Snow is doing a good job," presidential spokesman Scott McClellan said, referring to comments Bush made in a roundtable interview with financial reporters.

Snow in a separate interview refused to directly answer a question about how long he planned to remain in the administration.

"That is a subject for me and the president. As all Cabinet secretaries, I serve at the pleasure of the president," Snow said on CNBC.

Snow's comments marked a change in tone from last week when the first published reports began appearing that he could be forced to resign as part of an administration shakeup engineered by new White House chief of staff Joshua Bolten.

Last week, Snow had said, "I don't think it's helpful to make a comment on rumors from nameless sources."

The speculation about Snow's job security gained new momentum this week after Bush, with Snow sitting in the room, dodged a question from reporters about whether Snow would be staying in the Cabinet. Bush did praise Snow for being "a valuable member of my administration."

Asked about Bush's comments, Snow said, "It's nice to have your boss endorse you. So I appreciated that vote of confidence."

Snow refused to comment on whether he and Bush have talked about his future, saying, "Those would be private conversations and since they are private, they shouldn't be made public."

A number of names from Wall Street and Washington have been floated as possible successors including Henry M. Paulson Jr., the head of Goldman Sachs, the same top Wall Street investment firm once headed by Robert Rubin, who served as Treasury secretary for Bill Clinton.

"I know Mr. Paulson. He is a very able executive, a friend of mine. But I am not going to comment on rumors," Snow said.

Snow, the former head of railroad giant CSX Corp., has been Treasury secretary since February 2003, taking over from Paul O'Neill, who was forced to resign because of policy disagreements with the White House.

Snow has been a loyal proponent of the administration's economic policies, traveling the country as a salesman for Social Security reform and an overhaul of the tax code. But his standing suffered as both proposals stalled.