US credibility damaged by CIA tape affair, lawmakers

"Burning tapes, destroying evidence ... I don`t know how deep this goes. Could there be obstruction of justice? Yes," Republican Senator Chuck Hagel said on CBS.

"How far does this go up in the White House, who knew it? I don`t know," Hagel said.

The White House has stopped short of denying any involvement in the affair, after the CIA admitted last week to the destruction of the tapes in light of a New York Times report.

Aides said that Bush "has no recollection" of being told about the tapes before the CIA chief briefed him last week.

Senator Joe Biden, a Democratic presidential hopeful, said an independent counsel should investigate the incident instead of the newly-appointed attorney general, Michael Mukasey, who has sidestepped questions about whether "waterboarding" constitutes torture.

"He`s the same guy who couldn`t decide whether or not waterboarding was torture, and he`s going to be doing this investigation," Biden told ABC television.

Rights groups and Democratic lawmakers say waterboarding -- which simulates drowning -- amounts to torture and should be banned.