LONDON - A British tabloid reported Tuesday that it had been handed documents about security arrangements for the London Olympics that were left on a train by a police officer, the latest in a series of embarrassing mishaps involving British authorities misplacing government documents.

London police confirmed Tuesday that one of its officers lost a bag containing documents on Jan. 5 and reported it to his bosses, but downplayed the incident, adding that the papers were not "operationally sensitive."

"Obviously the loss of restricted material is a matter for concern, but we are satisfied that this does not compromise our security operation for the Olympics," police said in a statement.

The Sun newspaper said it received the documents from a passenger who found them on the train, and that it returned them to the police. It says the papers contain accounts of meetings where security measures were discussed, and details of contingency plans for the Olympics.

The Sun published an image of some of the documents in its print edition, and described in sweeping terms some of the complaints police had about communications systems.

Olympics experts deemed the breach embarrassing.

"It will do nothing but undermine confidence in the Olympics security operation, already brought into question by the prospect of riots and terrorist attacks," said Ellis Cashmore, a professor of culture, media and sport at Staffordshire University in England. "With so much scrutiny, it's almost beyond belief that someone in a responsible position would be guilty of such crass absentmindedness."

The incident comes only a few weeks after London police experts managed to smuggle a fake bomb into Olympic Park in a security test. Olympic officials declined to comment directly on the matter, saying such "testing is standard practice" in all major security operations.

Security experts said that while such testing is routine, it underlined the constant and ongoing struggle faced by security forces to create a system that will safeguard the July 27-Aug. 12 event without making London feel like an armed camp.