No element of the rocket reached space, said a U.S. official, who based that conclusion on data collected by the United States from its first few moments aloft.
The above animation shows the launch zone. North Korean officials say the rocket carried a weather satellite into space.
But the world was watching-- with concern that it could be testing the capacity to reach Hawaii or other targets.
Now a search is on in the waters off the Korean peninsula to see if any debris can be found.
Tokyo, which had threatened to shoot down the rocket if it appeared to be threatening its territory, had called for restraint. But Prime Minister Yoshihiko Noda said Thursday, "We are fully prepared to deal with any contingency," according to the news agency Kyodo.
Countries that include the United States and South Korea see the launch as a cover for a ballistic missile test. International leaders had urged North Korea to cancel the launch, but Pyongyang refused to back down, insisting the operation is for peaceful purposes.
"This was supposed to be associated with (Kim Jong Un's) ascension to power. So for this thing to fail ... is incredibly embarrassing," said Victor Cha, former director of Asian affairs for the U.S. National Security Council and now a Georgetown University professor.
The launch occurred at 7:39 a.m. Friday, both Yonhap and YTN reported, citing South Korean officials.
Immediately afterward, the South Korean military dispatched helicopters and ships in an attempt to find debris related to the rocket launch, according to YTN.
"The wise thing would be for North Korea to avoid this provocative and ill-considered action, which is in blatant violation of international law and their international obligations," said U.S. Ambassador Susan Rice, who currently holds the U.N. Security Council's rotating presidency, prior to the launch.
At the United Nations, diplomats warned that Pyongyang would face further isolation if it went ahead.
In Washington, White House spokesman Jay Carney had said the launch would be a "significant and clear demonstration of bad faith" on the part of the North, making it impossible for the United States to follow through on the food-aid deal.
South Korea described the planned move as a "grave provocation" and said it would respond with "appropriate countermeasures." Meanwhile, the Philippines and South Korea ordered commercial planes and fishing boats to stay clear of the rocket's proposed path.
"This launch will give credence to the view that North Korean leaders see improved relations with the outside world as a threat to the existence of their system," U.S. Secretary of State Hillary Clinton said this week. "And recent history strongly suggests that additional provocations may follow."
A recent report from South Korean intelligence officials said that North Korea is planning a new nuclear test in the area where it staged previous atomic blasts.
The South Korean intelligence report noted that the two previous rocket launches that Pyongyang said were intended to put satellites into orbit were followed a few weeks or months later by nuclear tests.
The last time Pyongyang carried out what it described as a satellite launch, in April 2009, the U.N. Security Council condemned the action and demanded that it not be repeated.
Vitaly Churkin, Russia's U.N. ambassador, told reporters outside the Security Council chambers that members don't have "clear agreement" about what steps to take if the launch goes ahead. "But one thing I can tell you: We have unanimity of understanding that if it were to happen, that would be a clear violation of two Security Council resolutions."
And Rice warned, "Every time they go down a path such as this, their isolation intensifies, the needs of their people increase and they become more and more out of the bounds of the international community. That will be the case if they do so."
Meanwhile, Chinese Ambassador Li Baodong said countries need "to do everything possible to defuse tension rather than inflame the situation there." China is North Korea's leading ally.
The failed launch came amid North Korean preparations to mark the 100th anniversary of the birth of Kim Il Sung, the founder of North Korea who ruled the Communist state for more than four decades. His birthday on April 15, known as the "Day of the Sun," is a key public holiday.
CNN's Barbara Starr, Paula Hancocks and Richard Roth contributed to this report.
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