Sources tell Fox News that U.S. intelligence almost immediately knew the Sept. 11 attack on the U.S. Consulate in Libya was the work of terrorists.

That weekend, however, U.S. Ambassador to the United Nations Susan Rice, stated that the attack was spontaneous, and resulting from Muslims' outrage over an anti-Islam film.

Only in the last week has the Obama administration begun to publicly declare that the attack was terrorism.

Bret Baier reports that the Obama administration actually labeled the attack as terrorism immediately in order to unlock certain federal resources to speed up the response. Intelligence officials immediately suspected involvement by elements of al Qaeda's North African wing.

Since the attack, officials have continuously declined to discuss it in detail, citing an "ongoing investigation." But sources now tell Fox News that no FBI agents have been in the city since the attack.

Watch Bret's report from America's Newsroom: