North Korea has tested more missiles just hours after US President Joe Biden left Asia.

North Korea fired three ballistic missiles from Sunan, north of the capital Pyongyang, South Korea's chiefs of staff said on Wednesday.

The Japanese Coast Guard also reported at least two launches.

The rockets apparently landed outside of Japan's exclusive economic zone, the Japanese broadcaster NHK reported.

The tests came just hours after Biden left Japan following his first trip to Asia as president.

The United States had warned that North Korea appeared ready to conduct a weapons test during Biden's visit.

North Korea has been conducting an unusually large number of missile tests since the beginning of the year.

With the tests, North Korea violates UN resolutions.

Biden and his South Korean counterpart Yoon Suk Yeol agreed over the weekend to step up measures to deter the nuclear-armed state.

At the same time, they offered North Korea help to contain the first confirmed virus outbreak.