North Korea fired a long-range rocket over Japan on Sunday, provoking international outrage and triggering an emergency meeting of the UN Security Council as it succeeded in grabbing the world's attention.

The reclusive communist state's official media said a satellite had been launched into orbit, and it was now circling the earth transmitting revolutionary songs.

US President Barack Obama said the UN Security Council should deliver a strong message to North Korea for what analysts believe was effectively a test of a ballistic missile designed to carry a warhead potentially as far as Alaska.

The rocket launch is the first big challenge for Obama in dealing with the prickly North, whose efforts to build a nuclear arsenal have long plagued ties with Washington. North Korea tested a nuclear device in 2006.

"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," Obama, who is on a European tour, said in a statement.

Obama later said North Korea must be forced to change.  The 15-member UN Security Council will hold consultations on the launch at 3 pm EDT/1900 GMT on Sunday.

Addressings thousands of people in Prague, Obama commited himself to reducing the US nuclear arsenal and said Washington would seek to engage all nuclear weapons states in arms reduction efforts. The White House said Obama remained committed to six-nation talks to "denuclearise" North Korea.

South Korea branded the launch of the rocket a "reckless" act, Japan said it was "extremely regrettable" and the European Union "strongly condemned" Pyongyang's step.

China, the nearest the reclusive North has to a major ally, and Russia both called on all sides for calm and restraint.

Analysts said Washington and Tokyo may seek a UN resolution condemning the reclusive state's action, but they expect resistance to tougher action such as new sanctions from Beijing.

South Korea's Yonhap news agency quoted a government official in Seoul as saying the rocket appeared to have carried a satellite, which Pyongyang had all along insisted was its plan.

Analysts said the launch may bolster North Korean leader Kim Jong-il's authority after a suspected stroke last August raised doubts about his grip on power.

It wins North Korea the attention it has sought as the new US administration wrestles with recession and the war in Afghanistan, and it could strengthen Kim's hand in using military threats to win concessions from global powers.

"North Korea is likely to judge that its negotiating position has been strengthened now that it has both the nuclear and missile cards," said Shunji Hiraiwa of Shizuoka Prefectural University in Japan.

Washington, Seoul and Tokyo had said before the launch that in reality it would be a test of the Taepodong-2 missile, which is designed to fly an estimated 6,700 km (4,200 miles).

Japan said it stopped monitoring the rocket after it had passed 2,100 km (1,305 miles) east of Tokyo. In the only previous test flight of the Taepodong-2, in July 2006, the rocket blew apart 40 seconds after launch. - Reuters