President Barack Obama, asked on Wednesday about possibly revoking entertainer Bill Cosby's Presidential Medal of Freedom, the highest U.S. civilian honor, said there is no mechanism for doing so, but added no civilized country should tolerate rape.

Obama declined comment on the specific allegations against Cosby, who has been accused by a series of women of raping them after giving them a drug.

"I'll say this: if you give a woman, or a man for that matter, without his or her knowledge, a drug and then have sex with that person without consent, that's rape," Obama told a White House news conference.

He added that "any civilized country should have no tolerance for rape."

Cosby has never been criminally charged, and most of the allegations exceed the statute of limitations. His attorneys have denied the accusations.

Cosby testified in 2005 that he had obtained quaaludes with the intent of giving the sedatives to young women in order to have sex with them, according to court documents unsealed last week.

A national sexual-assault prevention group called PAVE has been gathering signatures asking the White House to revoke Cosby's medal, awarded in 2002.

"With respect to the Medal of Freedom, there's no precedent for revoking a medal. We don't have that mechanism," Obama told reporters. "And, as you know, I tend to make it a policy not to comment on the specifics of cases where there might still be, if not criminal, then civil issues involved."