The US has refused to immediately describe the attack on its consulate in Benghazi on September 11 as an act of terror, saying that it will wait for the probe to be over before reaching to any conclusion.
Four Americans, including the US Ambassador to Libya, were killed during the attack on its Consulate in Benghazi.
Washington so far has said that the protest was a result of an anti-Islam video made in the US, while some US lawmakers have said that the attack has the hallmark of that of al-Qaeda.
"I don't think we know enough. We are going to continue to assess. She (Susan Rice, US Ambassador to the UN) gave our preliminary assessment. We are going to have a full investigation now, and then we will be in a better position to put labels on things," said State Department spokesperson Victoria Nuland yesterday.
She said the FBI and the Libyan government, besides carrying out independent investigations, are also mutually "cooperating" over the case.
"The investigation is obviously going to lead us to the appropriate conclusions about precisely what happened and how it happened," Nuland said, pointing out that the US was "working well" with Libya in probing the attack.
Nuland said video of the controversial film was being used to whip up strong feelings in Egypt that could lead to demonstrations.
"It was on that basis that the charge took the precaution on the morning of September 11, or even before they came into work, of having most of the Embassy staff stay home that day well before the protests even began. So when we had the difficulties, there was actually minimal staff in the building because we were already alerted and we had alerted the Egyptians as well," she said.