North Korea has test-fired two mid-range ballistic missiles from its eastern coast, says South Korea.
The first launch was considered to have failed, travelling about 150km (90 miles) before landing in the sea.
The second, launched hours later, flew about 400km. Military officials in the South said both were intermediate-range Musudan missiles.
A confirmed successful test would mark a step forward for North Korea after four failed launches in recent months.
South Korea's Joint Chiefs of Staff said Seoul and the US were "carrying out an in-depth analysis" of the second launch, and did not say whether it was considered a success.
North Korea, which is developing nuclear weapons, is banned by UN resolutions from any use of ballistic missile technology.
South Korea's presidential office announced that it would hold a national security meeting to discuss the launch.