South Korea fired warning shots after, Seoul says, North Korean troops crossed their border. The soldiers then went back to the North, Seoul said.

"Our military issued warnings and fired warning shots, and the North Korean soldiers retreated," a South Korean Joint Chiefs of Staff official told reporters.

South Korea sent two helicopters to battle a wildfire inside the Korean Demilitarized Zone (DMZ), Seoul’s military said Friday, adding it had warned North Korea in advance of its firefighting mission along the heavily armed border area.