North Korea fired off two ballistic missiles from its west coast early Wednesday, the Defense Ministry said, with both appearing to have fallen outside Japan¡¯s exclusive economic zone.

Defense Minister Yasukazu Hamada said both missiles appeared to fly on irregular trajectories, with the first hitting a maximum altitude of 50 kilometers and traveling 550 km, and the second hitting a 50-km altitude before splashing down after flying some 600 km.

Hamada said Tokyo had protested the move, the latest in a spate of launches that the Defense Ministry said ¡°threaten the peace and security of Japan, the region and the international community.¡±

The defense chief said Japan was working with the U.S. and South Korea to analyze the launches. Seoul also confirmed the launch of what it said were two short-range ballistic missiles, while Washington said the U.S. commitment to the defense of South Korea and Japan ¡°remains ironclad.¡±

The rare early-morning launches came at 3:29 a.m. and 3:45 a.m., the Japanese Defense Ministry said, and followed a test last week of the North¡¯s Hwasong-18 solid-fueled intercontinental ballistic missile.

That missile, which was fired on a ¡°lofted trajectory,¡± flew for about 74 minutes ¡ª the longest known flight for a North Korean missile ¡ª hitting a maximum altitude of more than 6,000 km and landing in waters outside Japan¡¯s EEZ, which extends 200 nautical miles (370 km) from its coast.

The twin launches were largely overshadowed by the crossing into North Korea by a troubled U.S. soldier on Tuesday over the heavily fortified border with the South

It also came on the heels of an announcement Wednesday by a senior American official that a U.S. nuclear-armed ballistic missile submarine was visiting South Korea for the first time in more than 40 years.

That announcement came as the allies held the inaugural meeting of their Nuclear Consultative Group (NCG), which discussed information-sharing, coordination and planning in the event of a North Korean nuclear attack, earlier in the day.

The creation of the NCG ¡ª intended to reassure U.S. ally Seoul amid calls for developing its own nukes ¡ª came amid North Korea¡¯s unprecedented spate of weapons tests. Pyongyang has launched around 100 missiles since early last year.

North Korea has reacted angrily to the NCG, with the powerful sister of leader Kim Jong Un railing against the talks as a ¡°meeting openly discussing the use of nukes against¡± Pyongyang.