Diplomats on the UN Security Council have met over North Korea's rocket launch.
Earlier, Washington had called for ‘strong’ action and China and Russia both appealed for calm following today's launch which drew swift international condemnation.
North Korea said it launched an experimental communications satellite as part of a peaceful space programme.
'Our scientists and technicians succeeded in putting a satellite, the Kwangmyongsong-2, into orbit with the delivery rocket Unha-2, according to the national space development plan,' the Korean Central News Agency reported.
'The satellite is rotating normally in its orbit.'
South Korea said the rocket appeared to be carrying a satellite but Defence Minister Lee Sang-hee has told parliament that it failed to orbit.
He said: 'All three stages of the rocket fell into the sea. No object entered orbit.
'It was a failed attempt to put a satellite into orbit. South Korea and the United States will continue analysing the situation.'
US President Barack Obama said that North Korea had violated UN resolutions and increased its own isolation.
He urged Pyongyang to refrain from further 'provocative actions'.
'With this provocative act, North Korea has ignored its international obligations, rejected unequivocal calls for restraint, and further isolated itself from the community of nations,' said Mr Obama.
Later, speaking in Prague before talks with EU officials, Mr Obama said: 'North Korea broke the rules. Once again by testing a rocket that could be used for a long-range missile.
'This provocation underscores the need for action - not just this afternoon at the UN Security Council, but in our determination to prevent the spread of these weapons.
'Rules must be binding. Violations must be punished. Words must mean something.'
South Korea branded the launch of the rocket, seen by many powers as a disguised missile test, a 'reckless' act, Japan said it was 'extremely regrettable', and the EU 'strongly condemned' Pyongyang's step.
China and Russia have called on all sides to maintain calm and restraint.
Japan said it stopped monitoring the Taepodong-2 rocket after it had passed 2,100km east of Tokyo.
In its only previous test flight, in July 2006, the rocket blew apart 40 seconds after launch.
The first booster stage of the rocket appeared to drop into the Sea of Japan, some 280km west of the northern Japan coast, the prime minister's office said. The second appeared to fall into the Pacific Ocean.
UN Secretary-General Ban Ki-moon said: 'Given the volatility in the region, as well as a stalemate in interaction among the concerned parties, such a launch is not conducive to efforts to promote dialogue, regional peace and stability.'
Japan's chief cabinet secretary Takeo Kawamura said that even if the payload was a satellite, it would still violate UN resolutions on North Korean ballistic missile activity.
The British Foreign Secretary condemned the launch of a rocket as a 'hostile policy'.
David Miliband said: 'While Pyongyang continues to pursue a hostile policy towards the rest of the world, it cannot hope to take its rightful place within the international community.
'I strongly urge North Korea to cease immediately all further missile-related activity and commit to engaging constructively with international partners.'
