SEOUL, Korea, Republic Of -- North Korea on Sunday defied international warnings and launched a long-range rocket that the United Nations and others call a cover for a banned test of technology for a missile that could strike the U.S. mainland.

The rocket was fired from North Korea's west coast and tracked separately by the United States, Japan and South Korea. At an emergency national security council meeting in Seoul, the country's president called the firing an "intolerable provocation." North Korea calls its launches part of a peaceful space program and said its state media would soon make a "special announcement."

The launch came about two hours after an eight-day launch window opened Sunday morning. It follows North Korea's widely disputed claim last month to have tested a hydrogen bomb. Washington and its allies will consider it a further provocation and push for more tough sanctions. The United States and Japan quickly requested an emergency meeting of the UN Security Council on Sunday morning, saying Pyongyang violated a council ban on ballistic missile launches.

North Korean rocket and nuclear tests are seen as crucial steps toward the North's ultimate goal of a nuclear armed long-range missile arsenal. North Korea under leader Kim Jong Un has pledged to bolster its nuclear arsenal unless Washington scraps what Pyongyang calls a hostile policy meant to collapse Kim's government.

Defence Ministry spokesman Moon Sang Gyun said a South Korean Aegis-equipped destroyer deployed in the sea off the country's west coast detected the North Korean launch at 9:31 a.m. The rocket's first stage fell off North Korea's west coast at 9:32 a.m. and the rocket disappeared from South Korean radars at 9:36 a.m. off the southwestern coast. There was no reported damage in South Korea.

Yonhap news agency and YTN TV in the South earlier reported that the rocket may have failed, but provided no other details. The South Korean government couldn't immediately confirm the reports and said it was trying to assess what happened with the United States.

The U.S. Strategic Command issued a statement saying it detected and tracked a missile launched on a southern trajectory but it did not pose a threat to the United States or its allies. A U.S. official, speaking on condition of anonymity because he wasn't authorized to be quoted by the media, said it may take days to assess whether the rocket was a success.

Japan's NHK broadcaster showed footage of an object visible in the skies from the southern island of Okinawa that was believed to be the rocket. Japanese chief Cabinet spokesman Yoshihide Suga told reporters that no debris fell on Japanese territory.

The global condemnation began almost immediately.

South Korean President Park Geun-hye said the launch was an "intolerable provocation." She said the North's efforts to advance its missile capabilities were "all about maintaining the regime" in Pyongyang and criticized the North Korean leadership for ignoring the hardships of ordinary North Koreans.

Japanese Prime Minister Shinzo Abe said Japan "absolutely cannot allow this," and told reporters at the prime minister's residence: "We will take action to totally protect the safety and well-being of our people."

U.S. National Security Adviser Susan Rice said in a statement that "North Korea's missile and nuclear weapons programs represent serious threats to our interests -- including the security of some of our closest allies -- and undermine peace and security in the broader region."

Kim Jong Un has overseen two of the North's four nuclear tests and three long-range rocket tests since taking over after the death of his father, dictator Kim Jong Il, in late 2011. North Korea says its rocket launches are satellite missions, but the U.S., South Korea and others say they are a covert test of ballistic missile technology. The UN Security Council prohibits North Korea from nuclear and ballistic missile activity. Experts say that ballistic missiles and rockets in satellite launches share similar bodies, engines and other technology.

The Jan. 6 nuclear test has led to another push in the UN to tighten sanctions. North Korea in 2013 also did a nuclear test and then unnerved the international community by orchestrating an escalating campaign of bombast, including threats to fire nuclear missiles at the U.S. and Seoul.

The Korean border is the world's most heavily armed and the rivals' navies occasionally trade gunfire near a disputed boundary in the Yellow Sea.

North Korea has spent decades trying to develop operational nuclear weapons.

It is thought to have a small arsenal of atomic bombs and an impressive array of short- and medium-range missiles. But it has yet to demonstrate that it can produce nuclear bombs small enough to place on a missile, or missiles that can reliably deliver their bombs to faraway targets.

Still, the North's nuclear tests and steadily improving long-range rocket launches push its nuclear aims further along.

North Korea has said that plutonium and highly enriched uranium facilities at its main Nyongbyon nuclear complex are in operation. The country is thought to have a handful of rudimentary nuclear bombs but there is debate about whether it is 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. After several failures, it put its first satellite into space with a long-range rocket launched in December 2012.

Six-nation negotiations on dismantling North Korea's nuclear program in exchange for aid fell apart in early 2009.

Under Kim Jong Un, a February 2012 deal for the United States to provide 240,000 metric tons of food aid in exchange for a freeze in nuclear and missile activities collapsed after a rocket launch by the North that April.

Associated Press writers Hyung-jin Kim and Kim Tong-hyung in Seoul; Yuri Kageyama and Eric Talmadge in Tokyo; Lolita Baldor in Washington, and Edith Lederer at the United Nations contributed to this report.