WASHINGTON (Reuters) -- Michael Mukasey should be denied Senate confirmation as U.S. attorney general unless the retired judge denounces as torture the interrogation technique known as waterboarding, a top Democrat said on Sunday.

Attorney General nominee Michael Mukasey arrives for his second day of Senate confirmation hearings on Capitol Hill in Washington, October 18, 2007. Mukasey should be denied Senate confirmation as U.S. attorney general unless the retired judge denounces as torture the interrogation technique known as waterboarding, a top Democrat said on Sunday. REUTERS/Jim Young

Senate Armed Services Committee Chairman Carl Levin said Mukasey must declare such simulated drowning to be unlawful while two more Republicans said the nominee should clearly stake out a position against waterboarding.

“He should not be confirmed unless he is very, very clear about these aggressive techniques, which violate our laws and violate (the international) Geneva (convention on treatment of prisoners of war), as being totally unacceptable,” Levin, a Michigan Democrat, told CBS’s “Face the Nation.”

Mukasey is expected to spell out his position this week in responses to written questions from members of the Senate Judiciary Committee.

Mukasey appeared headed toward easy confirmation as President George W. Bush’s nominee to succeed Alberto Gonzales as attorney general until he ran into trouble this month at the second day of his Senate confirmation hearing, much of it stemming to his response when asked about waterboarding.

The retired federal judge and former prosecutor from New York said torture violates the U.S. Constitution. But he declined to specifically say whether waterboarding is torture.

“If it amounts to torture, it is not constitutional,” Mukasey said, drawing complaints he was dodging the question.

Mukasey may likely still be confirmed. But a growing number of senators have said they want a definitive answer from him before passing judgment.

Critics have accused the United States of torturing suspects in the war on terrorism. Despite Bush’s assurances he prohibits torture, it’s unclear how detainees are treated since he has refused to disclose interrogation techniques.

Republican Sens. Lindsey Graham of South Carolina, a member of the Judiciary Committee, and John McCain of Arizona, a Republican White House contender, voiced concerns about Mukasey but neither said whether they may vote against him.

“I am convinced as an individual senator, as a military lawyer for 25 years, that waterboarding ... does violate the Geneva Convention, does violate our war crimes statute, and is clearly illegal,” Graham told “Face the Nation.”

“I think it would serve the attorney general nominee well to embrace that concept,” Graham said.

Asked if he would oppose Mukasey if the nominee refused to do so, Graham said, “If he does not believe that water boarding is illegal, then that would really put doubts in my own mind.”

McCain, appearing on ABC’s “This Week,” said, “Anyone who says they don’t know if waterboarding is torture or not has no experience in the conduct of warfare and national security.”

Asked if he would oppose Mukasey unless he declared waterboarding to be illegal, McCain said: “I can’t be that absolute, but I want to know his answer.”