North Korean troops have opened fire at a South Korean army post across the heavily-fortified border.
It is believed North Korean troops fired two rounds at a frontline guard post over the border in South Korea.
Exchanges of fire between the two sides erupt occasionally across the demilitarised zone dividing the two nations.
In this latest incident South Korean soldiers immediately returned fire.
It is not known if anyone was wounded.
Just hours earlier, Pyongyang warned that relations between the two Koreas would suffer a catastrophic impact if Seoul continued to reject military dialogue.ABC