President Yoon Suk Yeol said an incursion into South Korean airspace by North Korean drones was unacceptable and vowed to make the regime realize that it has a bitter price to pay for its provocations.

He said during a visit to the state-run Agency for Defense Development(ADD) on Thursday that only decisive retribution can deter aggression and acts that threaten freedom, and urged the nation to never fear or hesitate sending a clear message, even if the enemy has a nuclear arsenal or any weapons of mass destruction. 

Yoon was reiterating his comments from the previous day after he reproached defense minister Lee Jong-sup for failing to intercept the aerial vehicles from North Korea on Monday. The ADD is in charge of all developments for South Korea's military hardware and software, including military drones.

Attending the speech were his top military and security officials and advisers, including defense minister Lee, Yoon’s National Security Advisor Kim Sung-han, and the heads of the Army, the Navy and the Air Force.

Yoon called for a reinforcement of the country's response to all types of aerial vehicles that violate its sovereign airspace, as well as the military's plan to bolster its firepower amid the North's push to enhance its asymmetric warfare capabilities.

A pretense of peace cannot safeguard the nation’s security, and may even crack its very foundations, the president said, and to ensure true peace, the South should make "overwhelmingly superior war preparations."