The Air Force is investigating a sexual-assault report against a retired four-star general who was on active duty at the time of the alleged incident, service officials said Friday.

Details about the case are scant, but Air Force spokesman Col. Patrick Ryder said the service will conduct a thorough investigation of Gen. Arthur J. Lichte, who retired as head of Air Mobility Command in 2009. Ryder declined to provide additional details, saying it would be inappropriate to do so.

“I can tell you that the Air Force takes all allegations of sexual assault or harassment very seriously,” Ryder said in a statement. “We are committed to upholding the high standards and values of our service and ensuring an environment of dignity and respect, where sexual assault or harassment is not tolerated, and where there is clear accountability placed on all Airmen at every level.”

Lichte could not immediately be reached for comment Friday evening. A voicemail and email left for him were not returned.

The case was initially reported by John Q. Public, an independent blog that focuses on the Air Force. The blog said it had obtained an internal Air Force document that described a complaint filed earlier this year by a female colonel that her commander had “used his power to coerce sexual contact” three times between April 2007 and April 2009. The report said the senior officer at one point led Air Mobility Command, which has headquarters at Scott Air Force Base, which is about 20 miles east of St. Louis in Illinois.

If the Air Force moves forward with charges, it would probably become the most significant sexual-assault case involving a general in modern military history. A Pentagon report released in May said that the military had 6,083 reports of sexual assault in the fiscal year ending last October, representing a 1 percent decrease over the previous year. That figure included 5,240 reports by service members and 804 in which the victims were civilians or otherwise not in the military.

Congress and sexual-assault-prevention advocates have pressured the Pentagon for years to improve how it handles sexual-assault cases. Sen. Kirsten Gillibrand (D.-N.Y.), a frequent critic of the military’s response to the issue, released a report in May that said the military justice system remains dysfunctional in handling sexual-assault cases and prosecuted 22 percent of the 329 cases her office reviewed as part of an investigation focusing on four bases.

This story was updated with the general’s identity.

