North Korea announced Friday it would launch a rocket carrying a satellite next month, sparking widespread condemnation and US threats that it could put much-needed food aid in jeopardy.

The United States, Japan and South Korea said the plan, announced just 16 days after Pyongyang agreed to suspend long-range missile tests in return for the US food aid, would breach a UN ban imposed after previous launches.

Blast-off will be between April 12 and 16 to mark the 100th anniversary of the birth of founding leader Kim Il-Sung, the communist state's official news agency and state television said.

The US State Department called the proposed launch "highly provocative" and a threat to regional security.

And it voiced doubt over whether it could move ahead with providing food aid to North Korea if Pyongyang followed through with its threat.

"Were we to have a launch, it would create obviously tensions and that would make the implementation of any kind of nutritional agreement quite difficult," State Department spokeswoman Victoria Nuland said.

Nuland said that US diplomats told their North Korean counterparts prior to the February 29 agreement that a missile launch would be a "deal breaker."

The surprise deal, under which Pyongyang also promised to freeze its uranium enrichment plant, had raised hopes of eased tensions under the new regime headed by Kim Jong-Un, Kim Il-Sung's grandson, who took over the leadership after his own father Kim Jong-Il died on December 17.

But one analyst said Friday's announcement effectively killed off the agreement, under which the US was to give the hungry and impoverished nation 240,000 tonnes of food over a year.

The last long-range rocket launch on April 5, 2009, also purportedly to put a satellite into orbit, brought UN Security Council condemnation and tightened sanctions.

Pyongyang quit six-party nuclear disarmament talks in protest at the censure and conducted its second atomic weapons test the following month.

The North insists its satellite launches are for peaceful scientific purposes while the US and other nations call them disguised missile tests.

UN Security Council Resolution 1874, passed after the North's second nuclear test, demands that it "not conduct any further nuclear test or any launch using ballistic missile technology".

South Korea's foreign ministry said any launch would breach the resolution and be a "grave, provocative act".

Japan, whose airspace was crossed by the 2009 rocket, also said a launch would violate UN decrees and it would "strongly demand self-restraint".

Chinese vice foreign minister Zhang Zhijun met Ji Jae-Ryong, Pyongyang's ambassador, on Friday to express Beijing's worries, according to a statement from the Chinese foreign ministry, the official Xinhua news agency said.

"We sincerely hope parties concerned stay calm and exercise restraint," Zhang was quoted as saying. China is the North's main economic benefactor.

Fellow UN Security Council permanent member Russia also voiced concern and UN Secretary General Ban Ki-moon called on North Korea not to carry out the rocket launch. A spokesman said Ban was "seriously concerned".

The North said a Unha-3 rocket will launch a home-built polar-orbiting earth observation satellite known as Kwangmyongsong-3.

Repeating its arguments of 2009, it said such satellites assist economic development and are in line with the peaceful use of space.

The launch "will greatly encourage the army and people... in the building of a thriving nation", it added, as it prepares a mass celebration for the April 15 centenary and the young Kim tries to burnish his image as a strong leader.

"A safe flight orbit has been chosen so that carrier rocket debris to be generated during the flight would not have any impact on neighbouring countries," it said.

The North said the rocket would be launched southward from a new site it has been developing at Tongchang-ri on the northwest tip of the country.

The Unha-3 is known outside the North as the Taepodong-3 and is theoretically capable of reaching US territory, said Baek Seung-Joo of the Korea Institute for Defence Analyses.

Kim Yong-Hyun, of Seoul's Dongguk University, said the North would insist its launch was for peaceful scientific purposes and unrelated to the missile test moratorium.

But Daniel Pinkston, Seoul-based analyst with the International Crisis Group, said the announcement means the February agreement with the United States "is pretty much dead".