President Bush's father says claims he used his influence to keep his son out of the Vietnam War are "a total lie." Former Sen. Bob Kerrey (search), a decorated Vietnam veteran, says the current president should condemn ads claiming the Democratic presidential candidate fabricated elements of his wartime service.

Bush served stateside in the Texas Air National Guard (search ) during the Vietnam War while John Kerry commanded a Swift boat and was wounded three times during the conflict.

In an interview aired Wednesday on CBS's "The Early Show," the president's father dismissed claims that he helped his son stay out of the conflict.

"They keep saying that and it's a lie, a total lie," former President George H.W. Bush said. "Nobody's come up with any evidence, and yet it's repeated all the time."

Kerrey, who lost his leg in Vietnam, said the current president should denounce anti-Kerry ads being run by a group called Swift Boat Veterans for Truth (search ).

"These guys hate John Kerry," Kerrey, who represented Nebraska in the Senate, said in an interview on NBC's "Today" show. "This hatred is destructive. I think the president should condemn these ads for that reason."

Kerrey, a member of the Sept. 11 commission that investigated the attacks and suggested an overhaul of the nation's intelligence structure, also said Republicans are coming close to exploiting the tragedy for political gain. In particular, he said, parts of former New York Mayor Rudolph Giuliani's (search ) speech to the Republican convention were "right on the edge."