An inquiry into the September 11 attack in Libya that killed the US ambassador and three other Americans has said security arrangements were “grossly inadequate”.

The independent panel blamed systematic management and leadership failures at the State Department for the attack on the mission in Benghazi.

The report singled out the Bureau of Diplomatic Security and the Bureau of Near East Affairs for criticism.

It said there appeared to have been a lack of co-operation and confusion over protection at the mission in a country that had been left relatively lawless after the revolution that toppled Muammar Gaddafi.

The report found the number of Diplomatic Security staff in Benghazi before and on the day of the attack “was inadequate despite repeated requests … for additional staffing”.

Despite those failures, the Accountability Review Board said no individual officials ignored or violated their duties and recommended no immediate disciplinary action.

But it also said poor performance by senior managers should be grounds for disciplinary recommendations in the future.

The two most senior members of the panel – Retired Ambassador Thomas Pickering and a former Joint Chiefs of Staff chairman, Admiral Mike Mullen – are set to testify behind closed doors before the House and Senate foreign affairs on Wednesday.

Their testimony will set the stage for open hearings the next day with Deputy Secretary of State William Burns, who is in charge of policy, and Deputy Secretary of State Thomas Nides, who is in charge of management.

Secretary of State Hillary Clinton was to have appeared at Thursday’s hearing but cancelled after fainting and sustaining a concussion last week while recovering from a stomach virus that dehydrated her.

The report appeared to break little new ground about the timeline of the Benghazi attack, during which Libyan Ambassador Christopher Stevens, information specialist Sean Smith and former Navy Seals Glen Doherty and Tyrone Woods were killed.

But it confirmed that, contrary to initial accounts, there was no protest outside the consulate and said responsibility for the incident rested entirely with the terrorists who attacked the mission.

In the immediate aftermath, administration officials linked the attack to the spreading protests over an anti-Islamic film made in the US that had begun in Cairo, Egypt, earlier that day.

The review board found there had been no immediate, specific tactical warning of a potential attack on the 11th anniversary of the 2001 terrorist attacks.

However, the report said there had been several incidents of concern in the run-up to the attack that should have set off warning bells.

The report made 29 recommendations to improve embassy security, particularly at high-threat posts.

Mrs Clinton said she accepted all the recommendations.

[adrotate banner=”46″]