Authorities who conducted a three-year investigation of the deals said undercover FBI agents posed as weapons dealers, put up a Singapore arms broker in a four-star Inner Harbor hotel, arranged for him to attend religious services at a mosque in Laurel and invited him to test-fire machine guns at a Harford County firing range.

The FBI's ruse led representatives of LTTE to transfer $700,000 to the undercover agents as a down payment for millions of dollars in military-grade hardware, including sniper rifles, submachine guns, night-vision goggles and grenade launchers. The dealers also inquired about buying unmanned air vehicles and surface-to-air missiles.

"Terrorists must not be permitted to use the United States as a source of funding or equipment," Maryland U.S. Attorney Rod J. Rosenstein said in a statement after the sentencing. "We will continue to utilize all possible means to prevent terrorism, including undercover operations targeting people who attempt to obtain munitions in violation of our laws."

Another associate, Haji Subandi, 71, a citizen of Indonesia, was sentenced in December to 37 months in prison for his role in the conspiracy, as well as for two counts of money laundering and attempted exportation of arms and munitions. Varatharasa, 36, who is Sri Lankan, was sentenced to 57 months in prison for conspiracy and attempted arms exportation. Bin Osman, 55, from Singapore is scheduled to be sentenced in August on conspiracy and money laundering charges.

The State Department designated the LTTE a foreign terrorist organization in 1997. The organization cannot legally raise money or buy sensitive military equipment in the United States.