* Rocket passes Japan at least 2,100 km east of Tokyo
* U.S. military, South Korea say launch was unsuccessful
* Obama, world leaders condemn action
* Emergency Security Council meeting called
* China and Russia call on all sides to exercise restraint
By Linda Sieg and Jack Kim
TOKYO/SEOUL, April 5 North Korea fired a long-range rocket on Sunday, provoking international outrage and prompting the U.N. Security Council to call an emergency meeting.
The reclusive communist state said a satellite was launched into orbit and circled the earth transmitting revolutionary songs. But both the U.S. military and South Korea said it had failed to enter orbit.
Analysts say the launch was effectively a test of a ballistic missile designed to carry a warhead potentially as far as Alaska.
It was the first big challenge for U.S. President Barack Obama in dealing with the North, whose efforts to build a nuclear arsenal have long plagued ties with Washington.
"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 said, speaking on a European tour.
Addressing a crowd in Prague, Obama committed himself to reducing the U.S. nuclear arsenal and said Washington would seek to engage all nuclear weapons states in arms reduction efforts.
Obama remained committed to talks to "denuclearise" North Korea, the White House said.
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. NATO condemned it as "highly provocative".
"This is a regime that has placed itself outside international law," French President Nicolas Sarkozy said.
"There is only one response possible: the union of the international community must punish a regime that doesn't respect any international rules."
China, the nearest the North has to a major ally, and Russia called on all sides for calm and restraint.
The U.N. Security Council will hold consultations on the launch at 3 p.m. EDT/1900 GMT on Sunday. U.N. diplomats said no country was considering imposing new sanctions but a resolution on stricter enforcement of earlier measures could be discussed.
The United States, Japan and South Korea see the launch as a violation of a Security Council resolution passed in 2006 after Pyongyang's nuclear test and other missile tests. That resolution, number 1718, demands North Korea "suspend all activities related to its ballistic missile programme".
Both Russia and China have made clear they would block new sanctions by the Security Council, where they have veto power.
Chinese Foreign Minister Yang Jiechi called officials in the United States, Russia, Japan and South Korea to discuss the launch, the Foreign Ministry said.
"All sides ought to look at the big picture (and) avoid taking actions which may exacerbate the situation further," a Chinese statement said.
The North Korean launch was unsuccessful but that did not change the response the United States is seeking at the United Nations, a U.S. official said.
"NEGOTIATING HAND STRENGTHENED"
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).
The U.S. Northern Command said stage one of the missile fell into the Sea of Japan and the remaining stages along with the payload landed in the Pacific Ocean. No debris fell on Japan.
The command assessed the launch vehicle was not a threat to North America or Hawaii and took no action in response.
South Korea earlier said the rocket appeared to be carrying a satellite but Defense Minister Lee Sang-hee later told parliament that it failed to orbit, Kyodo news agency reported.
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.
Analysts said the rocket 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 U.S. 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.
The U.S. arms control coordinator, Gary Samore, said the North Korean launch meant missile defence would stay a priority.
"The North Korean test illustrates the importance of continuing to develop missile defence in order to protect... both the country and our allies in Asia," Samore told reporters.
U.N. Secretary-General Ban Ki-moon said the launch was not conducive to peace and stability and called on North Korea to return to six-country talks on ending its nuclear programmes.
Stephen Bosworth, U.S. special envoy for North Korea, said before the launch he hoped to bring Pyongyang back to the talks once the "dust" had settled.
While the talks among the two Koreas, China, Japan, Russia and the United States were central to efforts to get North Korea to give up its nuclear programme, Washington was ready for direct contact with Pyongyang, he said.
The talks stalled in December and Pyongyang has threatened to quit them if the United Nations imposes any punishment over the launch.
Park Jong-kyu, an economist at the Korea Institute of Finance in Seoul, said the impact on financial markets when they reopen on Monday would most likely be short-lived or negligible.
(Additional reporting by Jon Herskovitz and Kim Yeon-hee in Seoul, Rodney Joyce in Tokyo, Caren Bohan and Matt Spetalnick in Prague and Louis Charbonneau at the United Nations, Editing by Angus MacSwan)