SEOUL: North Korea fired two short-range ballistic missiles into the East Sea on Wednesday, after the arrival of an American nuclear ballistic missile submarine here and the inaugural session of a new South Korea-US security dialogue, Seoul's military said.

The Joint Chiefs of Staff (JCS) said it detected the launches from the Sunan area in Pyongyang between 3.30 a.m. and 3.46 a.m., and they flew some 550 km before splashing into the sea, reports Yonhap News Agency.

The JCS condemned the launches as "acts of significant provocation" that harms peace not only on the Korean Peninsula but also in the international community, and as a "clear" violation of UN Security Council resolutions.

"Our military will maintain a firm readiness posture based on capabilities to respond overwhelmingly to any North Korean provocations," it added.

The missile launch came after South Korea and the US held the inaugural meeting of the Nuclear Consultative Group (NCG) in Seoul the previous day to bolster Washington's extended deterrence commitment to using the full range of its military capabilities, including nuclear weapons, to defend Seoul.

The meeting coincided with the arrival of USS Kentucky at a key naval base in Busan, 320 km southeast of Seoul, marking the first port visit by an American nuclear-capable strategic submarine (SSBN) since USS Robert E. Lee in March 1981.

Pyongyang had test fired a Hwasong-18 solid-fuel intercontinental ballistic missile on July 12.