Testifying in closed session before the House Armed Services Committee, Col. George Bristol contradicted claims by some congressional Republicans he had issued a stand-down order following the attack, in which U.S. Ambassador to Libya J. Christopher Stephens and three other Americans were killed, The Hill reported.
Bristol, who commanded Joint Special Operations Task Force-Trans Sahara at the time of the attack, said he gave the Tripoli security team leader, Lt. Col. S.E. Gibson, permission to act freely in response to the attack, The Hill said, citing a description it had received of the committee's members-only briefing.
Gibson told Congress last month he was ordered not to send his team to Benghazi because they were needed in Tripoli in the event of an attack on the U.S. Embassy.
Republicans argue the United States wasn't prepared to respond adequately to the Benghazi attack.
They accuse the Obama administration of downplaying or covering up the administration's handling of the attack, its lead-up and aftermath during the heat of the 2012 presidential campaign.
"Colonel Bristol has experience that could be valuable in deepening our understanding of the events of that day," a committee source told The Hill.
"Of particular interest to the committee is what our posture was in the weeks and months that preceded the attack," the source said.
Bristol, a seasoned combat commander, stepped down from his task force commander post in March.
When House Subcommittee on National Security Chairman Jason Chaffetz, R-Utah, and Senate Armed Services Committee member Lindsey Graham, R-S.C. -- two vocal critics of the administration's Benghazi response -- requested Bristol appear, they were told 3 1/2 weeks ago he retired July 1 and could not be ordered to testify.
But Marine Corps Times reported July 17 Bristol had not yet retired and was still on active duty until the end of July.
Marine Corps spokeswoman Maj. Shawn Haney confirmed Bristol would in fact retire Aug. 1.
A Pentagon spokesman said the "initial confusion" over Bristol's status was due to a "personnel administrative error."
"The Department of Defense has fully cooperated with congressional requests to understand the attacks on the Benghazi compound," Pentagon spokesman Maj. Robert Firman said, adding Bristol would "be available to meet with House and Senate members and their staffs."
CBS News reported Tuesday Bristol already met with Graham.
Congress plans more Benghazi-related hearings after its August recess.