SEOUL, South Korea — North Korea fired a long-range rocket Wednesday morning in its second launch under its new leader, defying warnings from the U.N. and Washington only days before South Korean presidential elections.

North Korea declared the launch of a rocket and satellite a success, and state television planned a special broadcast about the launch at noon.

South Korean and Japanese officials confirmed that liftoff took place shortly before 10 a.m., while the United States did not immediately comment on it. Each nation had been urging North Korea to refrain from a launch widely seen as a cover for a test of banned ballistic missile technology.

South Korean Defense Ministry spokesman Kim Min-seok told a nationally televised news conference that a South Korean Aegis-equipped destroyer deployed in the Yellow Sea detected the launch but South Korea still didn’t know the launch was successful. North Korea had indicated technical problems with the rocket earlier and had extended its launch window to Dec. 29.

Japan said one part of the rocket fell into waters west of the Korean Peninsula and another part fell in the sea east of the Philippines. South Korean President Lee Myung-bak planned an emergency national security council meeting Wednesday, and Japan protested the rocket launch.

North Korean leader Kim Jong Un took power after his father Kim Jong Il died on Dec. 17 last year, and the launch also comes about a month before President Barack Obama is inaugurated for his second term.

The North says the Unha rocket was meant to put a satellite in orbit. A similar launch in April broke apart shortly after liftoff, and the condemnation that attempt received is likely to be repeated. Washington sees the launch as a cover for a test of technology for missiles that could be used to strike the United States.

Rocket tests are seen as crucial to advancing North Korea’s nuclear weapons ambitions. North Korea is thought to have only a handful of rudimentary nuclear bombs. But Pyongyang is not yet believed capable of building warheads small enough to mount on a missile that could threaten the United States.

North Korea has spent decades trying to perfect a multistage, long-range rocket. Experts say that ballistic missiles and rockets in satellite launches share similar bodies, engines and other technology. This is the fifth attempt at a long-range launch since 1998, when Pyongyang sent a rocket hurtling over Japan. Previous launches of three-stage rockets weren’t considered successful.

Washington sees North Korea’s pursuit of nuclear weapons and ballistic missiles as a threat to world security and to its Asian allies, Japan and South Korea.

North Korea under new leader Kim has pledged to bolster its nuclear arsenal unless Washington scraps what Pyongyang calls a hostile policy.