South Korea's army chief has reportedly ordered a crackdown on homosexual soldiers after a video showing one male soldier having sex with another surfaced on social media.

The Center for Military Human Rights Korea, a civic group, claimed the army has begun to track soldiers based on their sexual preferences. It added that the Army Chief of Staff Gen Jang Jun-gyu has directed the military to punish homosexual soldiers for violating military regulations.

Up to 50 soldiers are on a list of homosexual individuals, the group said. Under the country's military law, soldiers found guilty of "sodomy" or "other disgraceful conduct" can be punished for up to a maximum of two years in prison, according to the Yonhap news agency.

"Launching an investigation solely based on one's sexual orientation is discrimination and an act against humanity. The army made the list without material evidence of them having sexual intercourse," said the South Korean group. The army denied the accusations, but admitted it launched a probe over the video.

Some of the rounded-up army members were reportedly even asked whether they used condoms during their sexual encounters in what was branded a serious invasion of privacy. "This case shows the army's vulgar perception on one's sexual orientation and that the clause, whose constitutionality has continued to be questioned, can be abused to hunt out homosexuals," the Center said.

The South Korean military said in a statement: "The investigation team launched the probe after recognising that an incumbent soldier uploaded a video of him having sexual intercourse with another male soldier on social media." The army said it did not divulge any specifics involved in the incident to protect the identities of the people involved.

The army said it did not divulge any details about the incident to protect the identities of the people involved.