FBI Director Robert Mueller contradicted sworn testimony by Attorney General Alberto Gonzales on Thursday, saying that the government's terrorist surveillance program was the topic of a 2004 hospital room dispute between top Bush administration officials.

Mueller told the House Judiciary Committee on Thursday that he arrived at the bedside of then-Attorney General John Ashcroft shortly after Gonzales and Andrew Card had spoken with Ashcroft.

Gonzales was President George W. Bush's legal counsel at the time. Card was chief of staff.

Gonzales testified Wednesday that he and Card were talking about a different anti-terrorism program with Ashcroft and denied that the pair had pressured Ascroft to sign off on the program.

Mueller testified Thursday that Ashcroft sided against the two White House officials and with then-Deputy Attorney General Jim Comey, who believed the eavesdropping program, known as TSP, was illegal.

Ashcroft had handed off his official duties to Comey before entering hospital for surgery.

"Did you have an understanding that that the conversation was on TSP?" Rep. Sheila Jackson Lee, D-Texas, asked Mueller.

"I had an understanding the discussion was on a NSA program, yes," Mueller answered.

The news capped a day of challenges for the White House and its attorney general.

Earlier, a group of Senate Democrats called for a special counsel to investigate whether Gonzales perjured himself regarding the firings of U.S. attorneys and administration dissent over Bush's domestic surveillance program.

"We ask that you immediately appoint an independent special counsel from outside the Department of Justice to determine whether Attorney General Gonzales may have misled Congress or perjured himself in testimony before Congress," four Democratic senators wrote in a letter Wednesday.

"We do not make this request lightly," wrote Sens. Charles E. Schumer of New York, Dianne Feinstein of California, Russ Feingold of Wisconsin and Sheldon Whitehouse of Rhode Island in a letter to Solicitor General Paul Clement.

"His inability to answer simple, straightforward questions" during sworn testimony before the Senate Judiciary Committee "was just stunning," Schumer said in a news conference.

Accusing Gonzales of having "dissembled and deceived" senators on the committee, Schumer said "enough is enough."

"He told half-truths, part-truths and everything but the truth over and over and over again," Schumer said.

"I have never seen an attorney general so contemptuous of Congress," Feinstein added.

A spokesman for Senate Majority Leader Harry Reid, D-Nev., said he supports the request.

Also Thuirsday, Senate Judiciary Committee Chairman Patrick Leahy said Thursday he will subpoena White House political adviser Karl Rove to testify about the firings of the federal prosecutors. "We have now reached a point where the accumulated evidence shows that political considerations factored into the unprecedented firing of at least nine United States Attorneys last year," Leahy said.

In response, White House spokesman Tony Fratto said, "Every day congressional Democrats prove that they're more interested in headlines than doing the business Americans want them to do. And Americans are now taking notice that this Congress, under Democratic leadership, is failing to tackle important issues," he said. E-mails released by the Justice Department show Gonzales' aides conferred with Rove on the matter.

• July 24, 2007: Gonzales Hammered On Inconsistencies
• July 10, 2007: Gonzales Knew Of Patriot Act Abuses
• June 11, 2007: No-Confidence Vote On Gonzales Fails
• May 24, 2007: Dems Set Mid-June Vote On Gonzales
• May 23, 2007: AG's Former Aide: 'I Know I Crossed A Line'
• May 18, 2007: White House: Dems Gonzales Vote 'Stunt'
• May 17, 2007: Dems Seek No-Confidence Vote On AG
• May 16, 2007: Ashcroft Revelations Draw Fire On Gonzales
• May 16, 2007: Ashcroft Revelations Draw Fire On Gonzales
• May 15, 2007: Gonzales Deputy McNulty To Resign
• May 10, 2007: Gonzales Gets Grilled Again Over Firings