The FBI, in an undercover sting operation, has arrested a Moroccan man suspected of plotting to a suicide bombing at the U.S. Capitol in Washington, D.C., NBC news reports.

U.S. officials said the arrest "was the culmination of a lengthy and extensive operation during which the individual was closely and carefully monitored,"

The suspect was arrested at a steakhouse on Constitution Avenue near the Capitol, CNN reports.

NBC Justice correspondent Pete Williams says the suspect, described as being in his early 30s, had been under observation for several months.

Williams says the suspect was arrested by the FBI after receiving a vest that he thought contained explosives, but were actually inert materials.

Fox news reports that the suspect was carrying the vest when he was arrested in Washington.

NBC and Fox report that the suspect thought that the FBI agents who were assisting him were associates of al-Qaeda.

FBI agents had arrested another man back in September for allegedly plotting to attack the Capitol with remote controlled airplanes.

http://www.nbcwashington.com/news/local/Alleged-Suicide-Bomber-Arrested-in-DC-139527143.html