The U.S. Air Force says it disciplined five former commanders at a Texas base for not reporting problems quickly or taking appropriate action in what has turned into the military branch's worst sex scandal.

The confirmation came as the 18th military trial in the scandal started Wednesday.

A former wing commander, a former group commander and three former squadron commanders, as well as a senior noncommissioned officer, were disciplined last autumn after an investigation into instructor sexual misconduct at Joint Base San Antonio-Lackland, said Maj. Lori Hodge, a spokeswoman for the Air Education and Training Command. In some cases, a commander was not informed of problems in a timely manner and at other times a commander didn't take appropriate action after knowing about a problem, she said.

Their names and how they were disciplined were not revealed because they didn't go through the military court system, Hodge said. Federal privacy laws prohibit the Air Force from discussing administrative actions, which include counseling, admonitions and reprimands and are not considered punishment, Hodge said.

None were assigned to Lackland at the time of the discipline, she said. As of last summer, about three dozen Lackland instructors had lost their jobs in the previous year, but base officials said most were not removed for sexual misconduct.

A group commander and a squadron commander also were removed from command.

Col. Glenn Palmer was ousted in August as attention to the scandal intensified. He had arrived at Lackland in 2011 and was in charge when allegations involving more than a dozen instructors began to mount within his 737th Training Group, where he was group commander. In June, the Air Force relieved Lt. Col. Mike Paquette as commander of the 331st Training Squadron that also had been under scrutiny. A military attorney described it as a loss of confidence in Paquette's leadership.

Every new American airman reports for eight weeks of basic training at Lackland. About one in five trainees are women, and most of the nearly 500 instructors are men. Between 30,000 and 40,000 airmen graduate each year.

Although the sexual misconduct at Lackland apparently began in 2009, allegations came to light in June 2011, when basic military training instructor Staff Sgt. Luis Walker was accused of sexually assaulting a trainee, according to Gen. Edward A. Rice Jr., commander of the Air Education and Training Command who ordered the independent probe of all training units last year.

Walker was sentenced to 20 years in prison after being convicted of raping one female recruit and sexually assaulting several others.

So far, 17 instructors at Lackland have been convicted of misconduct with trainees _ from fraternizing to sexual assault, said Oscar Balladares, a Lackland spokesman. More cases are under investigation, he said.

Staff Sgt. Emily J. Allen, whose court-martial started Wednesday, faces up to a year in jail if convicted of charges that include having sex with a male trainee.