Washington:
A keenly awaited investigation into a deadly attack on the US consulate in the Libyan city of Benghazi is complete and has been given to Secretary of State Hillary Clinton, a spokeswoman said.
"The ARB has completed its work. Its report has been sent to the secretary this morning," State Department spokeswoman Victoria Nuland said, referring to the Accountability Review Board that Clinton tasked with the probe.
On September 11 heavily-armed militants stormed a US diplomatic compound in Benghazi, then attacked a nearby annex used by the CIA. Four Americans died in the assault, including US ambassador Chris Stevens.
Clinton appointed the ARB to investigate the incident amid allegations that the State Department had been lax in its security precautions in the restive city before the attack and at best sown confusion in its public response afterwards.
Republican lawmakers have demanded to know why administration officials initially portrayed the assault as a spontaneous demonstration against a film demonizing Islam, before later conceding that it was a planned terrorist act.
They have also questioned why the consulate and the annex did not have more security in place and why US special forces and air support were not ordered to deploy there from other bases once the attack was underway.