South Korea was investigating a leak from its top military intelligence command​ that ​local news media said had caused a large amount of sensitive information, including personal data on the command’s agents abroad, to end up in North Korea, its military said Saturday.

The military said in a brief statement that it planned to "deal sternly with” those responsible for the leak. But it declined to confirm the local media reports, pending its investigation of the Korea ​Defense Intelligence Command,​ where the leak took place.

The command, a secretive arm of the South Korean military, specializes in gathering intelligence on North Korea, a heavily militarized country that often threatens ​its southern neighbor with nuclear weapons.