Military authorities have launched an investigation targeting a Chinese national they suspect of bribing an active-duty soldier in an attempt to obtain military secrets.

According to the military on Thursday, the Defense Counterintelligence Command detained a Chinese national on Jeju Island on Saturday and is questioning the suspect over allegations that the person violated the Military Secret Protection Act.

The suspect is accused of approaching South Korean soldiers in a group chat room and posing as a soldier since early last year, offering money in exchange for military secrets.

An active-duty soldier serving in Yanggu County, Gangwon Province, is alleged to have brought an unauthorized cellphone into his unit to film internal data, such as plans for the ROK-U.S. joint exercises, after being recruited by the Chinese national.

The Defense Counterintelligence Command is expanding the investigation, as it suspects the Chinese national is a member of a larger group based in China, led by a ringleader who could be linked to the Chinese military.