Soldiers from North and South Korea have reportedly exchanged gunfire across their heavily armed border.
The South’s military says the North Korean frontline guardpost fired two shots at around 5.30 pm local time and the South returned fire three times.
It remains unclear why North Korea shot first and there are no reports of any injuries.
Relations between the two Koreas sank to the lowest level in years in March with the torpedoing of the South’s warship, killing 46 sailors.
There was also an exchange of artillery fire earlier this year at the disputed sea border.
On Friday, Pyongyang warned of a “catastrophic impact” if normal relations are not restored.
Tensions have eased in the past few months but the two sides remain at loggerheads over the North’s disputed nuclear programme.
Seoul is refusing to talk until Pyongyang admits being behind the warship attack.