South Korea's national security adviser and other top security officials held an emergency videoconference Sunday to discuss North Korea's firing of two projectiles believed to be short-range missiles, the presidential office said.

Chung Eui-yong, chief of the presidential National Security Office, presided over the session held at around 7 a.m., shortly after the North fired the projectiles into the East Sea from the coastal city of Wonsan.

Participants, including Defense Minister Jeong Kyeong-doo and National Intelligence Service chief Suh Hoon, shared information on the North's launches and instructed the military to maintain a watertight readiness posture, the presidential office said.

Cheong Wa Dae, however, did not convene a formal National Security Council meeting.

Deputy presidential spokesman Yoon Jae-kwan earlier said the presidential office is closely monitoring the situation.

"The (presidential) national security office is getting briefed frequently by the defense ministry and the national intelligence service on the North Korean projectile launch situation," he said in a text message to reporters.

Sunday's launches marked the North's fourth major weapons test this month, except for small artillery firing drills, amid stalled denuclearization talks with the US following the no-deal Hanoi summit in February last year.

"In a situation where the entire world is experiencing difficulties due to COVID-19, this kind of military act by North Korea is very inappropriate and we call for an immediate halt," the South Korea's Joint Chiefs of Staff said. (Yonhap)