South Korean President Yoon Suk-yeol yesterday said that any provocation by North Korea must be met with retaliation without hesitation despite its nuclear weapons, his office said, after an intrusion by North Korean drones.

Five North Korean drones crossed into South Korea on Monday, prompting South Korea's military to scramble fighter jets and attack helicopters to try to shoot them down, in the first such intrusion since 2017.

"We must punish and retaliate against any provocation by North Korea. That is the most powerful means to deter provocations," Yoon said in a meeting with his aides, according to his press secretary Kim Eun-hye. "We must not fear or hesitate because North Korea has nuclear weapons," he said.

Monday's intrusion triggered criticism in South Korea of its air defences. Yoon chided the military, in particular its failure to bring down the drones while they flew over South Korea for hours. South Korea responded on Monday by sending drones over North Korea for three hours.