WASHINGTON—Four members of Army special forces ready to head to Benghazi, Libya, after the deadly assault on the American diplomatic mission had ended were told not to go, according to a former top diplomat.

Gregory Hicks also argued in an interview with Republicans on the House Oversight and Government Reform Committee that if the U.S. military had flown aircraft over the Benghazi facility after it came under siege it might have prevented the second attack on the CIA annex that killed two CIA security officers.

Excerpts of the interview with the former deputy chief in Libya were released Monday in advance of Hicks' testimony on Wednesday before the panel.

The Sept. 11, 2012, assault killed Ambassador Chris Stevens and three other Americans. Nearly eight months later, Republicans insist that the Obama administration is guilty of a cover-up of the events despite a scathing independent report that faulted the State Department for inadequate security at the diplomatic mission.

Hicks' comments and the hearing are likely to revive the politically charged debate in which GOP lawmakers and outside groups have faulted former Secretary of State Hillary Rodham Clinton, a possible presidential candidate in 2016.