U.S. intelligence and defense 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.

- 10:30 p.m. Defense Secretary Leon Panetta and Army Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, are meeting with President Barack Obama at the White House and discussing the attack. Panetta returns to the Pentagon and has a series of meetings, including with Gen. Carter Ham, head of U.S. Africa Command.

- 11:11 p.m. A Defense Department surveillance drone aircraft - an unarmed Predator - that had been requested arrives over the consulate compound. Some time later a second drone arrives and takes over the mission.

- 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.

- 12:30 a.m. The first U.S. military unit is ordered to begin moving to Libya. By 3 a.m., two teams of special operations forces - one from Fort Bragg, N.C., and one from central Europe - and a Marine anti-terrorism unit are preparing to depart.

- 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. In the attack, the State Department also has said that a department computer expert, Sean Smith, was killed.

- 5:15 a.m. The team arrives at the CIA annex, with Libyan support, just before mortar rounds begin to hit the facility. Two CIA security officers - Tyrone Woods and Glen Doherty - 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.

- A military medical evacuation aircraft flies all of them out of Libya.