North Korea's keenly watched rocket launch has failed, Pyongyang has confirmed.

The rocket - seen by many as a banned test of long-range missile technology - was launched from north-west North Korea early on Friday.

The US, Japan and South Korea say it flew only for a short time before breaking up and crashing into waters off the Korean peninsula.

North Korea said its scientists were assessing what had caused the failure.

North Korea says the aim of the launch was to put a satellite into orbit - a move marking the 100th anniversary of the birth of national founder Kim Il-sung.

Analysis The failure of this launch is embarrassing for the North Korean regime. It had been billed as a sign of the North's technical achievement. But the news that it had failed was only given at midday local time. For four hours after the launch, there was no word at all. The international journalists assembled in the press centre were told nothing. Then state media said rocket scientists and technicians were looking into why it failed to reach orbit. In previous days we had been taken to see the launch pad on the West Sea site. North Korea wanted to insist this was just a satellite launch and not a test of missile technology as others had feared. It wanted to show us its mastery of technology. As well as being an embarrassment for North Korea's leaders, it has also drawn international condemnation. And there is more condemnation to come in the hours ahead.

But the US and other nations say the launch constituted a disguised test of long-range missile technology banned under UN resolutions.

In a statement, the White House condemned the launch, despite its failure. UN Secretary General Ban Ki-moon called the launch deplorable.

The UN Security Council is due to meet later in the day to discuss the launch. China, North Korea's closest ally, has called for calm and restraint on the Korean peninsula.

Meanwhile, North Korea's new leader Kim Jong-un has been appointed "first chairman" of the country's top decision-making body, the National Defence Commission, state media say. His late father, Kim Jong-Il, was made the commission's "eternal chairman" by the country's rubber-stamp parliament.

The move continues the transfer of power to Kim Jong-un from his father, who died in December.

Following the failed rocket launch, Kim Jong-un led tens of thousands of people in lavish celebrations in central Pyongyang at which giant statues were unveiled to his late father and grandfather.

Rocket debris

The 30m (100ft) Unha-3 rocket went up at 07:39 local time (22:39 GMT Thursday), South Korean officials said.

What has happened could not be more disastrous for North Korea Aidan Foster-Carter, Korea analyst, Leeds University

Its intended flight path would have taken it south, to the west of the Korean peninsula between Japan and the Philippines.

Both Japan and South Korea had threatened to shoot it down if it threatened their territory.

But officials from several nations observing the launch said the rocket had failed.

"Initial indications are that the first stage of the missile fell into the sea 165km (105 miles) west of Seoul, South Korea," the North American Aerospace Defense Command (Norad) said in a statement.

"The remaining stages were assessed to have failed and no debris fell on land. At no time were the missile or the resultant debris a threat."

Japan reported similar details.

"At approximately 07:40 we confirmed that a certain flying object was launched from North Korea and fell after flying for just over a minute," Japanese Defence Minister Naoki Tanaka said.

South Korea said the rocket exploded into some 20 pieces and fell into the sea.

"We are conducting a search operation to retrieve the fallen objects," a defence ministry official said.

Some five hours after the launch, North Korea confirmed it had been unsuccessful.

"The Earth observation satellite failed to enter its preset orbit. Scientists, technicians and experts are now looking into the cause of the failure," state-run KCNA news agency said. State television carried a similar announcement.

Space is hard - it's a truism and we've just seen further evidence of it

The BBC's Damian Grammaticas, who is one of a number of foreign journalists invited into North Korea for the launch, said the group had not been given any more information beyond that brief statement.

The rocket's failure, our correspondent said, is an embarrassment for the North Korean leadership.

It will also come, analysts say, as a relief to many countries who are worried about North Korea's potential to deliver weapons via long-range missiles.

'Provocative action'

The US said that North Korea's behaviour was of concern to the global community.

"Despite the failure of its attempted missile launch, North Korea's provocative action threatens regional security, violates international law and contravenes its own recent commitments," a White House statement said.

Pyongyang agreed in February to a partial freeze in nuclear activities and a missile test moratorium in return for US food aid. But that deal was put on hold last month after the North announced its rocket launch plans.

Earlier this week reports also emerged from South Korea of a possible third nuclear test being planned by North Korea.

North Korea conducted a similar rocket launch in 2009. On that occasion US and South Korean analysts said the rocket failed to reach orbit - but North Korea said it was a success.

The failure of this launch could pose a challenge for Pyongyang, which is holding a week of high-profile events ahead of the formal celebrations to mark Kim Il-sung's birthday on Sunday.

The Workers' Party held a rare conference on Wednesday ahead of the annual one-day session of the Supreme People's Assembly on Friday.

Both meetings are seen as formalising the transition of power to young leader Kim Jong-un following the death of Kim Jong-il.