The Pentagon on Friday released a timeline of its response to the Sept. 11 terrorist attack on the U.S. Consulate in Benghazi, Libya, pushing back arguments that the Defense Department did not move fast enough to thwart the assault.

The timeline shows that two to four hours after the attack had begun, the Pentagon ordered forces to “prepare to deploy” to Libya and a staging base in Sigonella, Italy. When those forces actually left their bases was not disclosed.

The timeline shows that the forces arrived in Libya and Sigonella long after the attack was over.

U.S. Ambassador J. Christopher Stevens and three other Americans were killed in the assault.

The release of the Pentagon’s timeline comes a week after the CIA issued its own chronology of the Sept. 11 attack, showing frenzied efforts to evacuate American personnel and fend off terrorists.

According to the Pentagon timeline:

• At 4:32 p.m. EDT, a Pentagon operations center notified Defense Secretary Leon E. Panetta and Army Gen. Martin Dempsey, chairman of the Joint Chiefs, after the first attack at the U.S. Consulate had begun at about 3:42 p.m.