The US has said North Korea will face "serious consequences" after launched a long-range rocket in defiance of international warnings.

Set off from the country's west coast only two hours after an eight-day launch window opened on Sunday morning, Pyongyang insisted the action was part of a peaceful space program and that it had successfully put a new Earth observation satellite into orbit.

But Susan Rice, US national security adviser, labelled the launch "reckless".

“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," she said in a statement.

"We condemn today's launch and North Korea's determination to prioritise its missile and nuclear weapons programs over the well-being of its people, whose struggles only intensify with North Korea’s diversion of scarce resources to such destabilising activities."

According to North Korean state TV, the Kwangmyongsong-4 satellite was now orbiting earth every 94 minutes.

The announcer added that North Korea - which carried out its fourth nuclear test last week - had a right to develop a “peaceful space programme” and that the satellite launch marked a “breakthrough in boosting our national defence capability”.

John Kerry, American Secretary of State, described it as a “provocation” and “destabilising” to peace. He said the US would work alongside the UN Security Council on “significant measures” to hold North Korea to account.

The rocket launched at around 9.30am Seoul time, and, according to Japan’s Fuji Television Network, a streak of light could be seen in the sky at China’s border with North Korea.

North Korea had notified UN agencies that it planned to launch a rocket carrying an Earth observation satellite, but the move was seen by opposition governments as a long-range missile test.

Everyday life in North Korea - in pictures Show all 10 1 /10 Everyday life in North Korea - in pictures Everyday life in North Korea - in pictures 'Ordinary life' in North Korea A man cuts the hair of a young boy at an apartment building in Pyongyang. High rise apartments are a common form of accommodation for people living in the capital city AP Photo/Dita Alangkara Everyday life in North Korea - in pictures 'Ordinary life' in North Korea North Koreans pause to give way for passing vehicles as they cross a road in Pyongyang. AP Photo/Dita Alangkara Everyday life in North Korea - in pictures 'Ordinary life' in North Korea North Koreans wait for public transportation at a bus stop in Pyongyang AP Photo/Dita Alangkara Everyday life in North Korea - in pictures 'Ordinary life' in North Korea A woman and her daughter walk past a North Korean flag hung on a utility pole as part of celebrations of the Liberation Day in Pyongyang AP Photo/Dita Alangkara Everyday life in North Korea - in pictures 'Ordinary life' in North Korea People attending the conference for national reunification as they observe their 70th anniversary of Korea's liberation, marking the end of World War II, in Panmunjom AFP PHOTO / KCNA via KNS REPUBLIC OF KOREA OUT Everyday life in North Korea - in pictures 'Ordinary life' in North Korea A man looks at items at a stamp shop in Pyongyang AP Photo/Dita Alangkara Everyday life in North Korea - in pictures 'Ordinary life' in North Korea North Koreans participate in a closing event for its celebration of the 70th anniversary of Korea's independence from Japan's 1910-45 colonial rule, at the truce village inside the demilitarized zone (DMZ) that divides the two Koreas in Panmunjom, North Korea. The country changed it's timezone on the occasion. North Korea introduced 'Pyongyang time' and pushed back its clocks by half an hour on 15 August, the same as before the Japanese occupation when the standard time used by the Korean empire was eight and a half hours ahead of GMT, instead of nine hours, which is Tokyo time EPA/KCNA SOUTH KOREA OUT Everyday life in North Korea - in pictures 'Ordinary life' in North Korea People attending the conference for national reunification as they observe their 70th anniversary of Korea's liberation, marking the end of World War II, in Panmunjom AFP PHOTO / KCNA via KNS Everyday life in North Korea - in pictures 'Ordinary life' in North Korea Youths and students attending an evening gala at the Kim Il-Sung Square in Pyongyang to celebrate the 70th anniversary of Korea's liberation, marking the end of World War II AFP PHOTO / KCNA via KNS REPUBLIC OF KOREA OUT Everyday life in North Korea - in pictures 'Ordinary life' in North Korea North Korean leader Kim Jong Un visits the Kumsusan Palace of the Sun to mark the occasion of the 70th anniversary of Korea's liberation REUTERS/KCNAATTENTION EDITORS

UN secretary Ban Ki-Moon called the launch “deplorable” and called on North Korea to halt its actions.

South Korea said that it would begin discussion on the United States on deploying an advanced missile-defene system to counteract North Korea's growing weapons capabilities. China, which considers North Korea an ally, also cautioned North Korea about its weapons and issued a statement saying it "expressed regret" over the launch.

Russia's Foreign Ministry issued a statement saying the launch could not but provoke a "decisive protest", adding Pyongyang had once again demonstrated a disregard for norms of international law.

"We strongly recommend the leadership of the Democratic People's Republic of Korea think about whether a policy of opposing the entire international community meets the interests of the country," the statement read.