SEOUL (Reuters) - North Korea has given global agencies notice of its plans to launch a satellite from April 4-8, an official said on Thursday in a move Washington has called provocative and views as a disguised long-range missile test.

Pyongyang gave notice it expects the first stage of the rocket to splash down in the East Sea, better known as the Sea of Japan, and the second stage to splash down in the Pacific Ocean, Yonhap news agency quoted sources familiar with the notice as saying.

The United States has said it could pursue a range of options against the North if it launches the missile, including squeezing it harder with U.N. sanctions imposed after separate missile and nuclear tests in 2006.

The launch notice adds to mounting tension on the divided Korean peninsula with Pyongyang saying it was on the edge of war, though many analysts doubt the North would send its poorly equipped military into a direct attack on the South.

North Korea said it has acceded to an international treaty on space exploration as part of its preparations for launching ... an experimental communications satellite, its KCNA news agency reported.

Lending a degree of credibility to Pyongyang's pledge to stage a rocket launch, the International Maritime Organization (IMO) said it had been contacted by the North about its plans.

We have received a letter and it contains dates, times and coordinates, Lee Adamson, a spokesman with the IMO said by telephone from London, confirming the dates as April 4-8.

He said a notice would soon be issued to maritime vessels, adding that the tests were scheduled to take place during daylight hours.

North Korea, which advised that the launch would take place from an east coast site that it had used for previous launches, said it had also notified the International Civil Aviation Organization so it could inform aircraft.

The U.S. Navy showed off to media on Thursday its Aegis-class destroyer USS Chaffee, which is in South Korea for joint South Korean-U.S. military drills and equipped to intercept missiles. Media reported last week that Japan and the United States might try to intercept any ballistic missile launched by the North.

The North says it would consider any shooting down of its rocket an act of war and has told South Korean commercial planes to keep away from its air space.

The North's official media has also described itself as the victim of planned aggression by South Korea and its U.S. ally, calling the joint military drills: madcap and reckless saber rattling ... in a bid to make surprise pre-emptive strikes.

Adding to Pyongyang's fury, the USS John C. Stennis aircraft carrier group is sailing off the south coast as part of the military exercises with the South, where the United States permanently stations about 28,000 troops.

FACE AT STAKE

Analysts said there were few technical differences between a satellite launch and a test of its longest-range ballistic missile, which use the same rocket, called the Taepodong-2 outside of the North.

The missile launch requires additional technology because the missile needs to be able to re-enter the atmosphere, said a defense analyst in Seoul who asked not to be named because of the sensitive subject matter.

North Korea shocked the region when it fired a Taepodong-1 over Japan in 1998.

Japan's Chief Cabinet Secretary Takeo Kawamura told reporters in Tokyo a North Korean rocket launch would violate U.N. resolutions, adding: it should cancel the launch.

The later Taepodong-2, whose first and only test flight in 2006 failed, is designed to carry a weapon as far as Alaska.

Experts said a launch looked inevitable, partly because the government wanted to flaunt a high-tech success at home and also display its prowess to the international community from which it is almost completely isolated.

They are putting themselves in a position where they have to keep going if they do not want to lose face, said Brad Glosserman, of the Hawaii-based Pacific Forum CSIS think tank.

Analysts said the North faced little risk of new punishments that could seriously damage its hardline leadership as it was likely China, about its only major ally, and Russia would use their Security Council veto power to block extra sanctions.

A ballistic missile launch would violate a U.N. Security Council resolution that forbids Pyongyang from further nuclear tests or ballistic missile launches.

Russian nuclear envoy Alexei Borodavkin told reporters in Seoul it was too early to say if a launch would violate existing U.N. resolutions and would depend on what the North fires.

South Korean officials said the North had been assembling the Taepodong-2 at a missile base on its east coast. The missile was still indoors but once set vertically and moved to a launch pad, it could be fired off in about seven to 10 days, experts have said.

(Additional reporting by Kim Junghyun and Jack Kim in Seoul and Yoko Nishikawa in Tokyo; Editing by Jonathan Thatcher and Jeremy Laurence)

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