Seoul on Top Alert As NKorea Rocket Launch Nears

The unification ministry, which handles , urged groups and individuals to avoid visiting the North from Saturday. Hundreds of South Koreans normally travel daily to a joint industrial zone.

The United States and its allies have warned Pyongyang not to go ahead with what it calls a satellite launch, vowing a stern response.

insists it is pursuing a peaceful space programme and analysts agree it will probably launch a satellite.

But opponents say Pyongyang's real purpose is to test the launch vehicle -- a Taepodong-2 ballistic missile which could reach Alaska or Hawaii -- in defiance of a UN resolution passed after the North's 2006 missile and nuclear tests.

A US defence official said there were indications the North is fuelling its rocket. The North has given a window of April 4-8 for what would be its third launch of a Taepodong-class rocket.

Washington made an 11th-hour appeal for a change of heart. State Department spokesman Robert Wood urged it "to desist from launching any type of missile.

"It would be counter-productive. It's provocative. It further inflames tensions in the region," he said Thursday. "We want to see the North get back to the six-party framework and focus on denuclearisation."

Japan made the same point.

"The test-launching of the missile will damage peace and stability in the region," Prime Minister Taro Aso told reporters Thursday after a G20 summit in London.

"The test-launching will constitute a violation of the UN Security Council resolutions and therefore it is not acceptable."

Aso, who has reportedly predicted a Saturday launch, stressed that if North Korea went ahead, "we must take up the matter firmly at the Security Council."

South Korea's weather agency forecast cloudy skies but no strong winds or rain this weekend for northeast North Korea, where the Musudan-ri missile base is located.

US President Barack Obama and his South Korean counterpart Lee Myung-Bak, who met Thursday on the sidelines of the G20, promised a "" response, according to Seoul officials.

An Obama administration official said any launch would see the United States seek to "firmly" respond at the United Nations.

The North has said it will roll back efforts to shut down its nuclear programme if the UN even debates the issue. It also threatens to "mercilessly deal deadly blows" at Japanese targets should Tokyo try to intercept its rocket.

Japan and the United States have deployed anti-missile Aegis destroyers to monitor the launch.

Tokyo has also deployed Patriot guided-missile units on land, but says it will only try to bring down the rocket should it start falling towards Japanese territory.

The North fired a shorter-range Taepodong-1 over Japan in 1998 as part of a failed satellite launch, and a longer-range Taepodong-2 in 2006. The 2006 test failed, with the missile exploding after 40 seconds.

This time around, "they are very confident the launch will be successful," said Daniel Pinkston, senior analyst with the International Crisis Group.

He said the Unha-2 (Galaxy-2), known in the West as a Taepodong-2, is a three-stage rocket around 32 metres (106 feet) tall and weighing about 80 tonnes.

It could potentially deliver a one-tonne warhead about 6,000 kilometres (3,750 miles).

Choi Choon-Heum, senior research fellow of the Korea Institute for National Reunification, told reporters Pyongyang wants to develop its intercontinental missile capability and induce Washington to hold direct talks.

Pinkston said domestic considerations are probably the dominant motive. "A successful launch would be a major psychological boost for the regime," he said.