Most European military sites equipped with U.S. nuclear weapons fail to meet Pentagon security requirements, according to a U.S. Air Force study.

The U.S. Air Force Blue Ribbon Review of Nuclear Weapons Policies and Procedures found fencing, security systems, lighting and support buildings in need of repair at several sites inspected by panel members, the February 8, 2008, report said.

The document was obtained by the Federation of American Scientists and posted on the group's Web site at www.fas.org.

"A consistently noted theme throughout the visits was that most sites require significant additional resources to meet DOD (U.S. Department of Defence) security requirements," the report said.

Hans Kristensen, director of the federation's Nuclear Information Project, said the security problems occurred at installations operated by the national militaries of Germany, Belgium, Holland and Italy, all NATO members. About 200 to 350 nuclear weapons are believed to be stored at the sites.

"What's really going on here is that the United States has changed its standards (since the September 11, 2001 attacks on the United States), but NATO has not followed and it's at the national bases we're seeing this problem," Kristensen said on Monday.

"In a way, it's the United States knocking on NATO's door and saying: 'C'mon, guys, you need to upgrade, too.'"

But he said some of the issues also stemmed from the fact that the primary mission of the squadrons involved is no longer nuclear deterrence but conventional operations in support of the global war on terrorism.

The Air Force had no immediate response to the findings, which were part of a broad review of U.S. nuclear weapons policies that included visits to 54 organizations and interviews with 822 people.

The review was commissioned by the Air Force in October 2007 after revelations that a U.S. bomber had mistakenly flown at least five nuclear warheads over the United States.

U.S. Air Force personnel at the sites maintain nuclear weapons that would be turned over to the military fighter wings of the host nations in times of war, Kristensen said.

In addition to problems in structural security, the Air Force review said security manpower in some places was provided by conscripts with as little as nine months of active duty experience and that unionized security personnel presented challenges at other locations.