A British citizen was arrested this morning on suspicion of being involved in a plot to smuggle surface-to-air missiles into the United States, ABCNEWS has learned. The person arrested allegedly sought to smuggle a Russian-made surface-to-air missile into the country and believed he was selling missiles to would-be terrorists, sources said. The name of the person has not been disclosed.

Sources said the man thought he was dealing with terrorists in the United States who wanted to shoot down a passenger jet.

The man was arrested in Newark, N.J., as part of an international sting conducted by the FBI, British and Russian authorities. The U.S. Secret Service also played a role.

Raids were also taking place in the United Kingdom but it is unclear what these yielded.

Here is the siezed weapon:

href=http://www.globalsecurity.org/military/world/russia/sa-18.htm>SA-18 Igla