Japan's government says North Korea launched two ballistic missiles on Monday morning.

Japanese Defense Minister Kishi Nobuo said North Korea fired a missile at around 8:49 a.m. Japan time, and then launched a second one at about 8:52 a.m.

Kishi said the missiles are believed to have reached a maximum altitude of around 50 kilometers. He indicated they likely flew about 300 kilometers, presuming they followed a normal ballistic trajectory. The missiles reportedly fell into the sea.

He said they likely landed near North Korea's east coast, outside Japan's exclusive economic zone.

Kishi said, "It is clear that North Korea is trying to improve its missile technology. The recent series of ballistic missile launches by the North represent a serious challenge for the entire international community."

The Japanese government has lodged a formal complaint through its embassy in Beijing.

South Korea's Joint Chiefs of Staff also said North Korea fired two projectiles, believed to be short-range ballistic missiles, eastward from a position outside the capital Pyongyang.

This is the fourth time North Korea has fired projectiles since the year started.