The White House has no information suggesting that the attack on the consulate in Benghazi was pre-planned, said spokesman Jay Carney at a press briefing on Friday. The statement contradicted earlier reports claiming the US State Department had credible information that American diplomatic missions might be targeted some 48 hours before the attacks on the consulate in Benghazi and the embassy in Cairo on Tuesday.

According to senior diplomatic sources quoted by the British newspaper The Independent, “The US State Department had credible information 48 hours before mobs charged the consulate in Benghazi, and the embassy in Cairo, that American missions may be targeted, but no warnings were given for diplomats to go on high alert and ‘lockdown’, under which movement is severely restricted.”

American officials now believe that the attack on the consulate in Libya resulted from a serious high-level security breach, since information regarding Ambassador Chris Stevens’ visit to the area was confidential, the paper said.

Stevens, along with three of his staffers, was killed Tuesday night when a mob of young men with guns and explosives attacked the consular compound.

Many senior US officials are increasingly convinced that the fatal incident in Benghazi was premeditated, and not the result of spontaneous anger at an anti-Islam film produced by a Coptic Christian American. There have been widespread reports that the attack was mounted by an Al-Qaeda affiliated group, and conceived to mark the eleventh anniversary of the 9/11 terror attacks and to avenge the deaths of senior Al-Qaeda figures.

According to Israel’s Channel 2 news analyst Ehud Yaari, the attack was planned to coincide with September 11, and was carried out in revenge for the killing of senior Al-Qaeda operative Abu Yahya al-Libi by US forces in June.

Patrick F. Kennedy, under secretary at the State Department, said he was sure the assault was planned due to its extensive nature and the use of weapons such as rocket-propelled grenades.

According to witnesses, there was little defense put up by local security forces meant to protect the diplomats. According to one nearby resident, “The security people just all ran away.”

Sensitive documents have gone missing from the Benghazi consulate since the attack, reported The Independent. Among them, lists of Libyans working with the Americans.

US officials have maintained since Tuesday that there was no advance warning or intelligence that would have warranted the boosting of security around diplomatic missions in Libya.

State Department spokeswoman Victoria Nuland said, “in advance of the September 11 anniversary and as we do every year, we did evaluate the threat stream and we determined that the security at Benghazi was appropriate for what we knew.”