Hameed (centre) was one of three men arrested in a sting

Moinuddeen Ahmed Hameed, 40, admitted conspiring to operate an unlicensed money transmitting business.

He was charged after FBI agents arrested suspected UK arms dealer Hemant Lakhani in New Jersey for allegedly trying to sell the missiles.

Hameed said he handled money for the deal but did not know what it was for.

He faces up to five years in prison and a fine of up to $250,000 when he is sentenced on 6 July.

Hameed was one of three people arrested in a sting operation by the FBI, British and Russian intelligence.

However, prosecutors accepted that he was a financial middleman who did not know the transactions involved illegal weapons.

Undercover operation

Mr Lakhani, 68, of London, was arrested near Newark airport in August last year by an FBI agent posing as a Muslim terrorist.

He has pleaded not guilty to charges of trying to sell 50 shoulder-fired missiles, which were capable of bringing down airliners.

He also denies offering to procure anti-aircraft guns, tanks, armoured personnel carriers, radar systems, C-4 explosives and a radioactive "dirty bomb".

Mr Lakhani, who was born in India, is due to appear in court again on 26 April. He faces up to 25 years in jail if convicted.

He is alleged to have planned to sell his "customer" anti-aircraft missiles from Russia and discussed how to best "terrorise" Americans with them.

He is charged with one count of "attempting to provide material support to terrorists", one count of unlawful brokering of foreign defence articles, two counts of money laundering, and one count of attempting to import merchandise into the US by means of false statements.

The investigation began in the months after the 11 September 2001 attacks on America.

Prosecutors are expected to submit more than 150 audio or video tapes as evidence against Mr Lakhani.

New York diamond dealer Yehuda Abraham, 76, has pleaded guilty to money-laundering in connection with the alleged missile smuggling plot and awaits sentencing.