SEOUL (AFP, REUTERS) - China and Russia on Wednesday (Feb 3) joined the global chorus of anger and concern over a planned rocket launch by North Korea, while Japan vowed to shoot down any missile that threatened its territory.

The reactions followed Tuesday's confirmation by Pyongyang that it would launch a rocket sometime between Feb 8-25, ostensibly aimed at putting an earth observation satellite into orbit, in what amounts to another major violation of UN resolutions just weeks after its fourth nuclear test.

"We express serious concerns about that," foreign ministry spokesman Lu Kang said in Beijing, calling on Pyongyang to abide by UN strictures forbidding its use of ballistic missile technology - even for ostensibly peaceful purposes.

Russia's Foreign Ministry said it was deeply concerned about North Korea's decision. "We must state that... the North Korean side demonstrates an outrageous disregard for the universally recognised norms of international law," the ministry said in a statement.

The North insists its space programme is purely scientific in nature, but the United States and its allies say its rocket launches are aimed at developing an inter-continental ballistic missile (ICBM) capable of striking the US mainland.

In South Korea the government echoed US warnings that the North would pay a "heavy price" if it went ahead, and Japanese Prime Minister Shinzo Abe condemned what he called a "serious provocation".

Seoul said the move would be a serious breach of UN resolutions and a "direct challenge" to the international community.

Abe condemned what he called a "serious provocation" that represented a clear violation of Pyongyang's international obligations.

The United States, which has been spearheading a diplomatic drive for harsher, more effective sanctions on Pyongyang, was quick to condemn the launch plan.

Mr Daniel Russel, the assistant US secretary of state for Asia-Pacific Affairs, slammed what he called "yet another egregious violation" of UN resolutions.

"This argues even more strongly for action by the UN Security Council and the international community to impose... tough additional sanctions," Mr Russel said.

"North Korea is defying the UN Security Council, it's defying its... neighbour China, it's defying the international community," he added.

In formal notifications sent to three UN agencies, including the International Maritime Organisation (IMO), North Korea said the launch would take place in the morning with a daily window of between 7.00 am-midday Pyongyang time (2230-0330 GMT).

The dates suggest a launch around the time of the birthday on Feb 16 of late leader Kim Jong Il, father of current leader Kim Jong Un.

The South Korean government statement urged Pyongyang to call off the launch immediately or pay a "heavy price" for threatening regional peace and stability.

North Korea successfully placed a satellite in orbit on a three-stage Unha-3 rocket in December 2012.

A fresh launch poses a dilemma for the international community, which has already spent the past month in a frenzy of diplomatic activity, seeking a consensus on how to respond to last month's nuclear test.

North Korea's chief diplomatic ally, China, has been resisting the US push for tougher sanctions, but a rocket launch would bolster calls for Beijing to bring its maverick neighbour into line.

China's top envoy on the North Korean nuclear issue, Mr Wu Dawei, arrived in Pyongyang for talks on Tuesday, just hours before the rocket launch notification was issued.

While its patience has been stretched to the limit by Pyongyang's refusal to curb its nuclear ambitions, China's overriding concern is a collapse of President Kim Jong Un's regime and the possibility of a US-allied unified Korea on its border.

US Secretary of State John Kerry met with his Chinese counterpart Wang Yi in Beijing last week and said they had agreed to mount an "accelerated effort" to resolve their differences over a UN resolution condemning the January nuclear test.

But Mr Kerry acknowledged that the two diplomats had not agreed on the "parametres of exactly what (a resolution) would do or say".

Since early 2013, North Korea has been upgrading its Sohae satellite launch complex to handle larger, longer-range rockets with heavier payloads, but most experts say Pyongyang is still years from obtaining a credible Inter-Continental Ballistic Missile capability.

"North Korea is still a long way off from being able to strike the US mainland," Mr Siegfried Hecker, one of the foremost authorities on Pyongyang's nuclear weapons programme, said in a recent interview.

"It has only had one successful space launch. It needs a lot more, but it has made a large effort in that direction," he said.

The flight plan coordinates sent to the IMO were similar to the December 2012 launch - suggesting an Unha-3 would again be the selected carrier.

The separated first stage was predicted to fall in the Yellow Sea around 200 km off the west coast of South Korea, followed by a second stage splashdown in the Philippine Sea.

Japan has said its military will shoot down any rocket that strays into its air space.