Prosecutors said El Khalifi had revealed his intention to kill Americans to an undercover FBI operative he thought was a member of the Al Qaeda terrorist group. He spoke of wanting to attack a synagogue and kill Army generals, prosecutors said, before settling on a plot to blow himself up inside the U.S. Capitol as an act of martyrdom. Officials have said the public was never in danger.

El Khalifi admitted in Friday's hearing that, in preparation for the planned attack, he detonated a test bomb at a quarry in West Virginia and told the undercover operatives that he was hoping for an even larger explosion when he attacked the Capitol. He told the operatives he would be happy if he could kill 30 people. He also asked his handlers to remotely detonate the suicide bomb at the Capitol if he were incapacitated.

El Khalifi's lawyer, federal public defender Ken Troccoli, declined comment after Friday's hearing. In earlier court papers, defense lawyers said they were exploring both the possibility of a plea deal or presenting an entrapment defense at trial.