FBI investigators still have not been granted permission to visit the consulate building where the U.S. ambassador and three other Americans were killed three weeks ago during an attack by Libyan militants in the eastern city of Benghazi.
An FBI team was dispatched to Libya within days of the attack, but they have been forced to remain in Tripoli as U.S. and Libyan officials argue over the terms under which the two sides will co-operate in the investigation.
