SEOUL: South Korea's President Yoon Suk Yeol on Tuesday called for stronger air defense and high-tech stealth drones to better monitor North Korea, a day after Seoul accused Pyongyang of flying five drones across their tense border for the first time in five years.

South Korea's military fired warning shots and scrambled warplanes and attack helicopters in response on Monday, but there has been no confirmation that any of the North Korean drones were shot down. That has raised a serious question about the South's air defense network at a time when tensions remain high over the North's torrid run of missile tests this year.