AbdulMutallab pleaded not guilty to new charges . New weapons and explosives charges are pending against AbdulMutallab . Prosecutors allege he then tried to ignite an explosive device made of PETN and TATP that was hidden in his underwear . He is accused of trying to set off an explosive device aboard a plane . The incident occurred on a plane flying into Afghanistan last Christmas .
AbdulMutallab pleaded not guilty to new charges . New weapons and explosives charges are pending against AbdulMutallab . He is accused of trying to set off an explosive device aboard a plane . The incident occurred on a plane flying into Afghanistan last Christmas .