The attack on the 11th anniversary of the Sept. 11, 2001 terror attacks on the United States by what is now suspected to be a group of al-Qaida-linked militants killed U.S. Ambassador Chris Stevens and three other Americans.
The timeline was offered just days before Tuesday's presidential election in a clear effort to refute recent news reports that said the CIA told its personnel to "stand down" rather than go to the consulate to help repel the attackers.
The officials told reporters that when the CIA annex received a call saying the consulate was under attack less than a mile (1.6 kilometers) away, about half a dozen members of a CIA security team tried to get heavy weapons and other assistance from the Libyans.
But when none was available, they went ahead with the rescue attempt. The officials said that at no point was the team told to wait.
The officials spoke on condition of anonymity because they were not authorized to provide intelligence information publicly.
The Obama administration's response to the attack on the consulate has been challenged by Republicans in Congress and elsewhere, questioning whether enough military and other support was requested and received.
And it has become an issue in the election, with President Barack Obama's Republican challenger, Mitt Romney, and Republican lawmakers accusing the White House of misleading Americans about the nature of the attack.
Initial descriptions of the attack suggested that it may have been linked to a protest over an American-made anti-Muslim film.
On Thursday, intelligence officials said they had early information that the attackers had ties to al-Qaida-linked groups, but did not make it public immediately because it was based on classified intelligence. And they said the early public comments about the attack and its genesis were cautious and limited, as they routinely are in such incidents.
They added that while intelligence officials indicated early on that extremists were involved in the assault, only later were officials able to confirm that the attack was not generated by a protest over the film.