WASHINGTON -- In the six months after the 9/11 attacks, up to 20 Cubans walked into U.S. embassies around the world and offered information on terrorism threats. Eventually, all were deemed to be Cuban intelligence agents and collaborators, purveying fabricated information.

A White House official complained bitterly and publicly in 2002 that Fidel Castro's agents had tried to send U.S. intelligence on ``wild goose'' chases that could cost lives at a time when Washington was reeling from the worst terrorism attacks in history.

But now two former U.S. government experts on Cuba have told El Nuevo Herald that the post-9/11 ``walk-ins'' were part of a permanent Havana intelligence program -- both before and long after 9/11 -- that sends Cuban agents to U.S. embassies to mislead, misinform and identify U.S. spies, perhaps even to penetrate U.S. intelligence.

``Many walk-ins were eventually identified as known/suspected [Cuban agents]. The problem was that U.S. intelligence was so starved for information on Cuba -- and we had so few Cuba experts -- that walk-ins were low risk, high payoff for the Cubans,'' said one former U.S. intelligence community official.

``The Cubans periodically used walk-ins to continue to test U.S. capabilities and reactions, but . . . later approaches were not as frequent as we saw in the immediate wake of the Sept. 11 attacks,'' added a former top Bush administration official.

Both asked that their names not be published because they were not authorized to speak on the topic.

In an average year, they said, Cuba sends about a dozen agents to walk into U.S. embassies around the world, claim to be defectors with important information and ask to speak with U.S. officials who can understand the value of their revelations. But the number can spike up to 20 to 25 at times of special importance, they added.

The year 2001 was certainly important. On Sept. 11, al Qaeda attacked the United States. Ten days later, U.S. authorities arrested the Pentagon's top Cuba analyst, Ana Belen Montes, on charges of spying for Havana.

Over the next six months alone, 15 to 20 Cubans walked into U.S. diplomatic missions and offered information heavily laced with references to terrorism threats, one of the Cuba experts said. ``All walk-ins in this group were eventually discredited,'' he added.

Most of the walk-ins took place in U.S. embassies in Latin America, Europe and Asia, the former Bush administration official said.

GUARDED SECRET

The CIA and the FBI's counterintelligence sections suspected many of the walk-ins were sent to penetrate U.S. intelligence in hopes of learning exactly how Montes was uncovered -- to this day one of the closest-held secrets in the case, one of the experts said.

``Their intelligence services had been taking a beating -- Montes in 2001, the five spies in Miami a couple of years earlier -- and we believed they were desperate to find out how they were being spotted,'' he added.

But most of the walk-ins over the years appear to have been part of a broader campaign: to make contact with U.S. intelligence agents, identify them, keep them busy and pass on misinformation, the two experts said. Any Cuban who walks into a U.S. embassy offering information is usually first interviewed by a low-ranking State Department official, the experts said. But if the information seems promising the visitor is later debriefed by a CIA or Defense Department official.