The members of K-pop boy band BTS will serve their mandatory military service, starting with the group's oldest member Jin, who turns 30 in December, their agency said on Monday.

"All other members will also serve mandatory military duty according to their plans," their management group HYBE said in a regulatory filing.

In August, a statement by South Korea's defense minister signaled that the country may shorten the duration of the mandatory military service for group members, also allowing them to perform their concerts abroad during their service.

The group announced last June that they were taking a temporary hiatus to pursue solo careers. When they announced their decision to disband, they promised to return one day and burst into tears.