A decade after the Pentagon declared a zero-tolerance policy for racist hate groups, recruiting shortfalls caused by the war in Iraq have allowed large numbers of neo-Nazis and skinhead extremists to infiltrate the military, according to a watchdog organization.

The Southern Poverty Law Center, which tracks racist and right-wing militia groups, estimated that the numbers could run into the thousands, citing interviews with Defense Department investigators and reports and postings on racist Web sites and magazines.

We've got Aryan Nations graffiti in Baghdad, the group quoted a Defense Department investigator as saying in a report to be posted today on its Web site, www.splcenter.org. That's a problem.

A Defense Department spokeswoman said officials there could not comment on the report because they had not yet seen it.

The center called on Defense Secretary Donald H. Rumsfeld to appoint a task force to study the problem, declare a new zero tolerance policy and strictly enforce it.

The report said that neo-Nazi groups like the National Alliance, whose founder, William Pierce, wrote The Turner Diaries, the novel that was the inspiration and blueprint for Timothy J. McVeigh's bombing of the Oklahoma City federal building, sought to enroll followers in the Army to get training for a race war.

The groups are being abetted, the report said, by pressure on recruiters, particularly for the Army, to meet quotas that are more difficult to reach because of the growing unpopularity of the war in Iraq.

The report quotes Scott Barfield, a Defense Department investigator, saying, Recruiters are knowingly allowing neo-Nazis and white supremacists to join the armed forces, and commanders don't remove them from the military even after we positively identify them as extremists or gang members.

Mr. Barfield said Army recruiters struggled last year to meet goals. They don't want to make a big deal again about neo-Nazis in the military, he said, because then parents who are already worried about their kids signing up and dying in Iraq are going to be even more reluctant about their kids enlisting if they feel they'll be exposed to gangs and white supremacists.

The 1996 crackdown on extremists came after revelations that Mr. McVeigh had espoused far-right ideas when he was in the Army and recruited two fellow soldiers to aid his bomb plot. Those revelations were followed by a furor that developed when three white paratroopers were convicted of the random slaying of a black couple in order to win tattoos and 19 others were discharged for participating in neo-Nazi activities.

The defense secretary at the time, William Perry, said the rules were meant to leave no room for racist and extremist activities within the military. But the report said Mr. Barfield, who is based at Fort Lewis, Wash., had said that he had provided evidence on 320 extremists there in the past year, but that only two had been discharged. He also said there was an online network of neo-Nazis.

They're communicating with each other about weapons, about recruiting, about keeping their identities secret, about organizing within the military, he said. Several of these individuals have since been deployed to combat missions in Iraq.

The report cited accounts by neo-Nazis of their infiltration of the military, including a discussion on the white supremacist Web site Stormfront. There are others among you in the forces, one participant wrote. You are never alone.

An article in the National Alliance magazine Resistance urged skinheads to join the Army and insist on being assigned to light infantry units.

The Southern Poverty Law Center identified the author as Steven Barry, who it said was a former Special Forces officer who was the alliance's military unit coordinator.

Light infantry is your branch of choice because the coming race war and the ethnic cleansing to follow will be very much an infantryman's war, he wrote. It will be house-to-house, neighborhood-by-neighborhood until your town or city is cleared and the alien races are driven into the countryside where they can be hunted down and 'cleansed.'

He concluded: As a professional soldier, my goal is to fill the ranks of the United States Army with skinheads. As street brawlers, you will be useless in the coming race war. As trained infantrymen, you will join the ranks of the Aryan warrior brotherhood.