Two leaders of an Albany mosque have been arrested in connection with an alleged plot to purchase a missile for use in a terrorist attack.

The suspects were arrested during a nighttime raid on a mosque and two private homes in Albany, New York. Deputy U.S. Attorney James Comey says the men were apprehended after a year-long undercover operation, one that is not related to the elevated terror threat in New York and Washington, DC.

"This is not a case where the defendants were discovered plotting terrorist violence," he explained. "The terrorist plot in this case is one that the government's agent, the cooperating witness, represented to be under way. It was not real."

According to court papers the two men agreed to help an FBI informant, posing as a terrorist, who said he intended to use a shoulder-fired missile to attack the Pakistani ambassador's office in New York City.

The first suspect, Mohammed Hossain, agreed to launder money for the sale of the missile through his pizza shop. He is a naturalized American citizen who was born in Bangladesh, and is the founder of the Albany mosque that was raided by U.S. agents.

Mr. Comey says the sting operation began when Mr. Hossain asked the FBI informant for help in getting a fake driver's license for a relative and then asked for a loan.

"The cooperating witness brought a shoulder-fired missile to a meeting with Mr. Hossain and explained that he imports such things, and ships them to New York City to the mujahideen brothers, implying terrorist operatives, to shoot down airplanes," Mr. Comey added. "The courts documents allege that Hossain agreed to help launder the money that the cooperating witness represented was going to be the proceeds of the sale of the missile."

The second suspect, Yassin Aref, witnessed the money exchange. Mr. Aref, an Iraqi citizen who was granted political asylum in the United States three years ago, is an imam at the same mosque.

Few details are known about the government's informant, whose identity is being concealed. According to the indictment, he was a non-U.S. citizen who had pleaded guilty to charges of fraud and was cooperating with authorities in order to reduce his own sentence.

Mr. Comey told reporters "this is not the case of the century," but he hopes it will send a message.

"We are working very, very hard to infiltrate the enemy," he said. "Our agents and our informants are putting a full court press on in this country and around the world. Anyone engaging in terrorist planning would be very wise to consider whether their accomplice is not really one of our guys."

The two men are being charged with providing material support to terrorists, and are being detained pending a hearing scheduled for next week. Family members say the suspects are peaceful men, and were not involved in a terrorist plot. If convicted, they could face up to 70 years in prison.