SEOUL, South Korea (AP) — South Korea says its troops have exchanged fire with North Korea along their tense land border.

The Joint Chiefs of Staffs in Seoul says North Korean troops fired several bullets at a South Korean guard post inside the heavily fortified border between the countries on Sunday.

The military says in a statement South Korea fired two rounds in response after issuing a warning broadcast.

It says South Korea suffered no casualties.

Sunday’s fire exchange took place a day after North Korea reported its leader Kim Jong Un’s first public appearance in about 20 days, ending intense speculation about his health.