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 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.
Timeline of events surrounding Libya rescue effortU.S. intelligence officials offered a timeline Thursday of the CIA's response to the attack on the U.S. Consulate in Benghazi, Libya, from its annex less than a mile from the diplomatic mission. U.S. Ambassador Chris Stevens and three other Americans were killed in the attack, which occurred on the 11th anniversary of the Sept. 11 terrorist attacks.
A minute-by-minute look at how the security teams' response played out. All times are local for Benghazi.
— 9:40 p.m. The CIA annex receives its first call that the consulate has come under attack.
— Less than 25 minutes later, the security team leaves the annex en route to the consulate.
— Over the next 25 minutes, team members approach the compound and attempt to get heavy weapons. When they cannot secure heavy weapons, they make their way onto the compound itself in the face of enemy fire.
— 11:11 p.m. A Defense Department surveillance drone — an unarmed Predator — that had been requested arrives over the consulate compound.
— 11:30 p.m. All U.S. personnel have departed the consulate except for Stevens, who is missing. The vehicles come under fire as they leave the facility.
— Over the next 90 minutes, the CIA annex comes under sporadic fire from small arms and rocket-propelled grenades. The security team returns fire, dispersing the attackers.
— Around 1 a.m., a team of additional security personnel from Tripoli lands at the Benghazi airport and attempts to find a ride into town. Upon learning that Stevens is missing and that the situation at the CIA annex has calmed, the team focuses on locating Stevens and obtaining information about the security situation at the hospital.
— Before dawn, the team at the airport finally manages to secure transportation and armed escort. Having learned that Stevens is almost certainly dead and that the security situation at the hospital is uncertain, the team heads to the CIA annex to assist with the evacuation.
— 5:15 a.m. The team arrives at the CIA annex, with Libyan support, just before mortar rounds begin to hit the facility. Two security officers are killed when they take direct mortar fire while engaging the attackers. The attack lasts only 11 minutes before dissipating.
— Less than an hour later, a heavily armed Libyan military unit arrives at the CIA annex to help evacuate all U.S. personnel and takes them to the airport.