Kim Yo Jong, sister of North Korean leader Kim Jong Un, called South Korea's expression of regret over alleged drone flights sensible but insufficient on Friday. The statement followed South Korean Unification Minister Chung Dong-young's expression of "deep regret" over the incidents that North Korea claims violated its sovereignty.

North Korea accused South Korea last month of launching surveillance drone flights in September and January, threatening retaliation. While the South Korean government denies operating drones during the specified times, authorities are investigating three civilians suspected of flying drones from border areas into North Korea. The development threatens to further dampen prospects for Seoul's push to resume long-stalled talks with North Korea amid a deepening nuclear standoff.

Kim Yo Jong warned that recurrence of such provocations would "surely provoke a terrible response" and that "various counterattack plans are on the table." The Unification Ministry said the alleged drone flights ran counter to the government's principles of reducing tensions and plans to take unspecified steps to prevent similar incidents. Analysts suggest North Korea's drone accusations may be aimed at increasing anti-South Korea sentiments ahead of the ruling Workers' Party congress in late February.