The political repercussions are continuing after the deadly assault on the US consulate in the Libyan city of Benghazi last September.
A senior US security official has now quit and three others have been suspended after a report criticised how the crisis was handled.
Certain state department offices were highlighted for their lack of co-operation.
Admiral Mike Mullen worked on the report. He told reporters: “We did conclude that certain State Department bureau level senior officials in critical positions of authority in Washington demonstrated a lack of leadership and management ability appropriate for senior ranks in their responses to security concerns posed by the special missions.”
The report blamed “grossly inadequate” security for the attack, which led to the deaths of Ambassador Christopher Stephens along with three other US officials.
Initially attributed to an anti-Islamic film, intelligence later linked the attack to al-Qaeda affiliates.