U.S. authorities say the men were part of a secret mission to help militants locked in the bloody civil war in their homeland by buying and smuggling hundreds of thousands of dollars worth of surface-to-air missiles. According to court papers, the men also wanted guns — but not just any guns.

"We need AK-47s, but only if you have Russian-made or American-made," prosecutors allege one defendant said during a meeting with an undercover agent posing as a crooked arms dealer. "Not the Chinese."

The videotaped sting is central to an unusual case against four alleged agents of the Liberation Tigers of Tamil Eelam, or "Tamil Tigers" — a Sri Lankan rebel force the State Department calls a terrorist organization.