A man travelling to the U.S. Capitol for a planned suicide attack has been arrested by authorities in Washington.

The suspect was stopped following a lengthy undercover operation by the FBI. Agents had been assisting the man in his plot, under the pretense that they were Al Qaeda associates, according to Fox News.

Officials also added that the man was not affiliated with any terrorist organization and was acting alone.

The public was never in danger, police said, according to CNN.