Washington ? Democrats labored to deflect attacks on John Kerry’s war record with fresh television ads touting his fitness for national command on Friday as the White House accused the Massachusetts senator of “losing his cool” over claims he lied to win military medals in Vietnam.

“John Kerry is a fighter, and he doesn’t tolerate lies from others,” spokeswoman Stephanie Cutter shot back at President Bush’s spokesman.

Undeterred, the anti-Kerry group that provoked the furor distributed a second commercial to the news media and said it would begin airing the ad next week in Pennsylvania, Nevada and New Mexico. The ad intersperses clips of a youthful Kerry talking about war atrocities during an appearance before Congress in 1971 with images of veterans condemning his testimony.

The Kerry camp on Friday filed a legal complaint with the Federal Election Commission, claiming the veterans’ group illegally coordinated with the Bush-Cheney campaign and with the Republican National Committee. They cited as evidence news reports linking some of the financiers behind the veterans’ group to Bush campaign officials. The Bush camp, the RNC and leaders of the veterans’ group have denied collaborating, which would be against the law.

The intense late-August maneuvering highlighted the closeness of the race for the White House and came as polls offered the first hint that the questioning of Kerry’s medal-winning service in the Vietnam War — allegations that he strongly condemned this week as lies — were taking a political toll.

One poll found that more than half the voters questioned had seen or heard of an ad by Swift Boat Veterans For Truth that accuses Kerry of lying about events that earned him five medals in Vietnam a generation ago. The University of Pennsylvania’s National Annenberg Election Survey also found that 44 percent of self-described independent voters found the ad very or somewhat believable.

Separately, a CBS poll found a sharp drop in Kerry’s support among veterans since the end of the Democratic Convention.

In a commercial that officials said was filmed Thursday, the Democratic Party showed retired Air Force General Merrill A. McPeak saying he had endorsed Bush four years ago but was backing Kerry now.

“John Kerry has the strength and common sense we need in a commander in chief,” says McPeak, a fighter pilot in Vietnam who rose to become Air Force chief of staff during the first Persian Gulf War in 1991.

That message is sharply at odds with the image portrayed in the anti-Kerry ad — the one the Massachusetts senator denounced on Thursday when he said Bush was relying on front groups to “do his dirty work.”

Vietnam War veterans, from left, Chuck Searcy, Andre Sauvageot, John Lancaster and Phil Karber try on Vote