South Korea's military fired warning shots after North Korean soldiers crossed the Military Demarcation Line near the border on Tuesday, according to the country's Joint Chiefs of Staff (JCS).
Some 20 to 30 soldiers breached the line by 20 metres (65 feet) inside the demilitarised zone on Tuesday morning and briefly moved back north after warning shots were fired by the South, according to a JCS official.
The JCS does not think the breach was intentional, the Yonhap news agency reported.
North Korean soldiers also suffered multiple casualties while working due to the explosion of landmines in the demilitarised zone, the JCS official told the press.

Turkey to host Gaza meeting amid ceasefire concerns
Tanzania opposition says hundreds killed in vote protests
Turkey sentences 11 people to life in prison over ski resort hotel fire
China sends its youngest astronaut to 'Heavenly Palace' space station
Israel launches more strikes on Gaza overnight, testing fragile truce
Trump-Putin summit cancelled, FT reports
Houthis say 43 detained UN staff to face trial over Israeli attack
Hurricane Melissa leaves 49 dead in Caribbean, churns north
