South Korean President Yoon Suk-yeol warned that North Korea will pay for “reckless” military aggression against the ROK on Friday, in an emotional speech marking a national mourning day for soldiers who died in past inter-Korean battles.

Yoon’s remarks for West Sea Defense Day followed the conclusion of large-scale U.S.-ROK Freedom Shield exercises on Thursday, and came as the allies are set to conduct a variety of follow-up drills in the coming weeks and months.