SEOUL: Five North Korean drones crossed into South Korea on Monday and South Korea responded by scrambling jets and attack helicopters and opening fire to try to shoot down the North Korean aircraft, the South Korean military said.

As part of its response, the South Korea military also sent surveillance aircraft into the North to photograph its military installations, a South Korean military official said.

“This is a clear act of provocation by the North violating our airspace,” a South Korean official with the Joint Chiefs of Staff, Lee Seung-o, told a briefing.

One of the five North Korean drones flew near the South Korean capital, Seoul, and the others flew near the west coast, Lee said the South Korea military “operated assets to shoot down” the drones.

He did not say if any drones had been shot down but the Yonhap news agency later said South Korea’s military fired about 100 shots but failed to shoot any down. Lee said South Korea initially fired “warning shots” when it first detected the drones.

One of the drones was known to have returned to North Korea while South Korea lost track of the other four, Yonhap reported, citing the Joint Chiefs of Staff.