North Korea fired a long-range rocket on Sunday, after days of speculation about a missile launch that boosts its nuclear ballistic missile technology.
Pyongyang claimed it launched an earth observation satellite into orbit, but the critics say it defied UN sanctions that bar it from conducting ICBM missile tests.
In Japan, Prime Minister Shinzo Abe said Pyongyang's action was "intolerable" and completely unacceptable.
In South Korea, President Park Geun-hye called for a national security council meeting after the rocket launch.
Earlier, the US had called for tougher sanctions against North Korea, while South Korea said any rocket launch will be a breach of UN resolutions and a "direct challenge" to the international community.
The rocket was launched on a southward trajectory, and it would likely pass over Japan's southern Okinawa islands, South Korea's Yonhap news agency reported.
Sunday's launch is the sixth long-range missile test by the North, which aims eventually to develop a nuclear armed long-range missile arsenal.
Three of these missile launches and two of its four nuclear tests were carried out under the rule of Kim Jong Un, the current dictator, who has strengthened his grip on power through many purges.
Early in January Pyongyang, which has been running a decades-old nuclear programme, claimed it successfully tested a hydrogen bomb.
North Korea has been attempting to build an intercontinental ballistic missile (ICBM) and its last rocket launch was in 2012, when it said it put into orbit a communications satellite.