But he made clear that if Democrats insist on including timetables again, he will not hesitate to bring out his veto pen.

"If they want to try again that which I've said is unacceptable, of course I won't accept it,'' the president said during a news conference here with Japanese Prime Minister Shinzo Abe. "I hope it won't come to that.''

In his opening statement, Committee Chairman Harry Waxman, a Californian Democrat, said he prefers to issue subpoenas as a "last resort," adding that he felt he had "hit a brick wall" with Rice.

"For four years, I have been trying to get information from Rice on a variety of issues, including the reference to uranium and Niger in the president's 2003 State of the Union speech," Waxman said.

"My request is simple: I would like Secretary Rice to suggest a date that would be convenient for her to testify before our committee," he said.

House Minority Leader John Boehner, a Republican from Ohio, quickly denounced the committee's actions, saying it is merely a "partisan show."

The committee also passed issuing subpoenas to Republican National Committee (RNC) chairman Mike Duncan and for the e-mails White House officials composed on RNC e-mail accounts with regard to the firing of eight U.S. Attorneys.

The committee's move is part of the Democratic-led Congress's ongoing investigations of the conducts of the Bush administration.

The Washington State Senate and House of Representatives approved the bill in March and early April respectively. Opponents of the measure claim it erodes the institution of marriage, but the bill's supporters stressed the importance of granting equal rights to same-sex couples. The bill is the latest step in Washington's pioneering stance on gay civil rights which includes a revision of the state's Civil Rights Act to include the phrase "sexual orientation" among the classes of people protected from discrimination in housing, lending, and employment.

Senate Judiciary Committee Chairman Patrick Leahy, a Democrat, said the U.S. Department of Justice is experiencing an unparalleled crisis of leadership. He said Gonzales has undercut the credibility of the rule of law in the United States.

Gonzales is trying to explain the different explanations he has given about his involvement in the firings. Other Department of Justice officials also have given contradictory reasons for the firings, at first saying they were performance-related, and then backing away from that rationale.

Critics say they believe the firings were politically motivated and that President Bush's senior political adviser, Karl Rove, was deeply involved.

The Bush administration has defended the firings, saying the prosecutors serve at the pleasure of the president.

In prepared testimony released Sunday, Gonzales apologized for mishandling the matter, and says he was "less than precise" in his statements.

Committee Democrats are focusing many of their questions on the role Gonzales and the White House played in the firings of two prosecutors in the western states of California and New Mexico.

Gonzales has said that the prosecutors were dismissed as part of a management review designed to improve leadership in the Justice Department.

Kyle Sampson, Gonzales' former chief of staff who has since resigned, told the Senate Judiciary Committee last month that the prosecutors were fired for political reasons rather than for poor performance as the Justice Department has claimed. Gonzales has defended his role in the firings, admitting that there has been some confusion but saying that his involvement in the matter was limited to signing off on recommendations made by Sampson.

Gonzales defended his role in the firings on Friday, admitting that there has been some confusion but that his involvement in the matter was limited to signing off on recommendations made by his former chief of staff Kyle Sampson. Sampson, who resigned last month, told the Senate Judiciary Committee Thursday that the prosecutors were fired for political reasons rather than for poor performance as the Justice Department has claimed. Sampson also said Gonzales did more than merely follow his recommendations, and that Gonzales and former White House counsel Harriet Miers were deeply involved in the firings. On Saturday Republican Rep. Lee Terry of Nebraska joined the call for Gonzales' resignation.