"North Korea is only further isolating itself by engaging in provocative acts, and is wasting its money on weapons and propaganda displays while the North Korean people go hungry," White House spokesman Jay Carney said.

The fact that the first US reaction came from Carney, and not a higher level official, or President Barack Obama, reflected a desire by top officials to deprive the Stalinist state of publicity or a propaganda reward for its action.

"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," Carney said.

"While this action is not surprising given North Korea's pattern of aggressive behavior, any missile activity by North Korea is of concern to the international community.

"The United States remains vigilant in the face of North Korean provocations, and is fully committed to the security of our allies in the region."

North Korea had said the rocket would place a satellite in orbit for peaceful research purposes, but Western critics see the launch as a thinly veiled ballistic missile test, banned by United Nations resolutions.

South Korea's Yonhap news agency said the rocket disintegrated into several pieces and the debris fell into the Yellow Sea off South Korea.

Carney repeated US statements that Obama was willing to engage North Korea, a headache for successive US presidents, but said Pyongyang must live up to international obligations to merit the fruits of US diplomacy.

"North Korea's long-standing development of missiles and pursuit of nuclear weapons have not brought it security -- and never will.

"North Korea will only show strength and find security by abiding by international law, living up to its obligations, and by working to feed its citizens, to educate its children, and to win the trust of its neighbors."

The White House did not immediately mention an already suspended deal to send food aid to the nuclear-armed North's impoverished population.

The scheme foundered after the North's announcement that it would launch the rocket, which Washington said proved Pyongyang could not be trusted.

A US official said on condition of anonymity that the fact that the missile launch was a propaganda move, and it failed, would have internal ramifications in the murky politics of the reclusive state.

During a trip to South Korea for a nuclear security summit last month, Obama raised eyebrows by saying it was unclear who was "calling the shots" in North Korea under its new leader Kim Jong-Un.

The official also suggested that the failure of the missile launch was a blow to Pyongyang as it would make customers for its ballistic missile technology think twice about buying its wares.

Japan and South Korea would like tougher action against the hardline state, which already faces UN sanctions over its two nuclear tests. But fears that the unpredictable North is preparing a new atomic bomb blast has clouded diplomatic outrage over Friday's failed rocket test.

"We have to hold our fire. This was bad, but we have to expect worse to come," said one senior UN envoy, referring to reports of a new underground nuclear test in the making.

The Group of Eight powers on Thursday condemned North Korea over its defiant rocket launch and said they would consider taking "appropriate actions" at the Security Council.

Foreign ministers of the club of industrial powers, who had just wrapped up a meeting in Washington that warned North Korea against a launch, issued a fresh statement saying the firing "undermines regional peace and stability."

The Security Council will meet on Friday at 1400 GMT to discuss the launch which ended with the North Korean rocket disintegrating and falling into the sea.

Permanent members of the 15-nation body -- Britain, China, France, Russia and United States -- have already held informal talks and the council is expected to pass a statement condemning the North's latest act.

Germany's Foreign Minister Guido Westerwelle, who was at the United Nations, said the launch "will increase tensions on the Korean peninsula" and the Security Council "must give a strong answer."

"But a diplomatic protest may be the best step at this stage," said a second UN diplomat, speaking on condition of anonymity because no decisions have yet been formally decided.

The United States, South Korea and Japan -- key players in the international showdown with North Korea -- have all called the rocket launch a "provocative act."

Even those who take a softer line on the North, such as Russia, agree that the launch was in breach of UN resolutions 1718 and 1874 which imposed sanctions after its first two nuclear tests in 2006 and 2009.

Only China, the North's last major diplomatic friend, has not openly said the launch breaches UN resolutions.

"We are very concerned about that issue and we have been working on that along with the friends, the countries, the parties concerned in the region," China's UN ambassador Li Baodong told reporters on Thursday.

"We think the peace and stability in the region is really important. We have got to do everything possible to defuse tension rather than inflame the situation there. I think we should do everything possible to make sure that peace and stability will be maintained in the region," he added.

South Korean officials say the North is making preparations near the town of Punggye-ri for a new nuclear test. The two previous atomic blasts were staged there.

"Recent satellite images led us to conclude the North has been secretly digging a new underground tunnel in the nuclear test site... besides two others where the previous tests were conducted," a South Korean government source recently told AFP.

After North Korea announced it would stage its rocket launch, the United States suspended a recent deal to offer food aid to the North in return for a freeze on some nuclear and missile activities.

Pyongyang in November 2010 an apparently operational enriched uranium plant, which could potentially give the North another way to make atomic weapons.