“Our military remains stuck in a barbarian and medieval culture,” said Lim Tae-hoon, director of the Military Human Rights Center. “The investigators preyed upon gay soldiers’ vulnerability like a cat playing with a mouse.”

Mr. Moon made the comment during a debate in which the issue of the military’s treatment of gays was raised. Under the conscript system, all eligible men are required to serve about two years.

But the Military Criminal Act outlaws sodomy and other unspecified “disgraceful conduct” between servicemen, whether or not there is mutual consent and whether or not that conduct takes place in or outside the military compounds. Those found to have violated the act face up to two years in prison.

The army declined to provide details of its investigation. It insisted that it was not cracking down on gay soldiers; instead it said that it was trying to root out sodomy and other homosexual activities, which right-wing Christian groups have called a growing blight on its readiness to fight North Korea’s 1.2 million-strong military.

But in the past week, evidence has emerged to support the allegations by gay soldiers that investigators flouted the army’s own regulations on how to treat gay service members by preying upon the soldiers’ fear of shame and abuse if they are outed in the military. Analysts and veterans said bullying, hazing and sexual violence were chronic problems.