I. Lewis "Scooter" Libby's allies urged President Bush on Wednesday to pardon the former White House aide, but Bush rebuffed questions about whether he would intervene to prevent Libby's 2 1/2-year prison sentence.

Libby, the former chief of staff to Vice President Dick Cheney, was sentenced Tuesday for lying and obstructing the CIA leak investigation. He became the highest-ranking White House official sentenced to prison since the Iran-Contra affair.

A Republican stalwart, Libby drew more than 150 letters of support from military commanders and diplomats who praised his government service from the Cold War through the early days of the Iraq war.

"The White House is well aware of what a lot of supporters of Scooter have to say about this," said Mel Sembler, who served as Bush's ambassador to Italy and now leads Libby's defense fund. "There really is only one answer. This man has to step up and pardon him."

Bush, traveling in Europe, gave no hint about his plans.

"Yesterday was a very sad day for Scooter and his family," Bush told reporters. "But there's an ongoing process and it wouldn't be appropriate for me to discuss it while the process is going forward."

"My heart goes out to his family," the president added.

Libby's lawyers are rushing to try to forestall the prison sentence. They planned to file papers on Thursday arguing that Libby should remain free while his appeals play out.

But that appears to be an uphill battle. Special Prosecutor Patrick Fitzgerald intends to oppose it and U.S. District Judge Reggie B. Walton said he sees no reason to grant a delay.

If the request were denied, Walton would order Libby to report to prison in the next month or so. That would force Libby's lawyers to rush to an appeals court in hopes of blocking his imprisonment.

Sembler and other supporters would not discuss what conversations they have had with White House officials.

"I hope the president feels sufficient pressure to issue a pardon," said Richard Carlson, another member of Libby's defense fund. Carlson was ambassador to the Seychelles during the administration of Bush's father.

Libby is "a man of principle, like him or not, and the principle in this case is that a pardon is the right thing to do," Carlson said.

Libby was convicted of perjury and obstruction of justice for lying to investigators about his conversations with reporters about CIA officer Valerie Plame.

Fitzgerald questioned Bush and Cheney in a probe that became a symbol of the administration's deepening problems.

"Mr. Libby was the poster child for all that has gone wrong in this terrible war," defense lawyer Theodore Wells said in court. "He has fallen from public grace. It is a tragic fall, a tragic fall."

Libby has maintained his innocence and said any false statements he made to investigators were the product of a faulty memory, not deception.

"It is respectfully my hope that the court will consider, along with the jury verdict, my whole life," he said in brief remarks in court before the sentencing. It was his first public statement about the case since his indictment in 2005.

Walton also fined Libby $250,000 and placed him on two years probation after his prison sentence expires. There is no parole in the federal system, but Libby would be eligible for release after two years.

Bush was in Germany for the Group of Eight summit with Germany, Canada, Britain, France, Italy, Japan, the United States and Russia. Sembler said he hopes the president will focus on Libby's pardon once Bush returns homes next week.

"It looks like that's the only way this is going to get resolved," he said.