North Korea warns spy planes off rocket site

North Korea today accused the United States of spying on the site of an impending rocket launch and threatened to shoot down any US planes that encroach into its airspace.

The Koreans say they will send a communications satellite into orbit on a multistage rocket between April 4 and 8.

However, the US, South Korea and Japan think the reclusive country is using the launch to test long-range missile technology, and have warned leaders in Pyongyang they face sanctions under a UN Security Council resolution banning the country from ballistic activity.

Pyongyang’s state radio accused US RC-135 surveillance aircraft of spying on the launch site on its northeast coast.

The broadcast said: “If the brigandish US imperialists dare to infiltrate spy planes into our airspace to interfere with our peaceful satellite launch preparations, our revolutionary armed forces will mercilessly shoot them down.”

It is unclear what capability North Korea has to shoot down the high-flying Boeing RC-135, which can reach altitudes of nearly 10 miles high, but the threat came a day after the North claimed the US and South Korea conducted about 190 spy flights over its territory in March, including over the sea off the launch site.

The US military in South Korea declined to comment on the spying allegations or the North’s threat.

Prime Minister Gordon Brown, in a summit with South Korean President Lee Myung-bak, yesterday said that any launch would breach the UN resolution and pledged to respond in step with Seoul.

Mr Lee, in London for the G-20 summit, told Mr Brown it is important for the international community to show a concerted response. Japanese Prime Minister Taro Aso also urged united action.

Japan has deployed battleships and Patriot missile interceptors off its northern coast to shoot down any wayward rocket parts that the North has said might fall over the area.

Tokyo has said it is only protecting its territory and has no intention of trying to shoot down the rocket itself.

However, North Korea said that if Japan tries to intercept the satellite, the North’s army “will consider this as the start of Japan’s war of re-invasion ... and mercilessly destroy all its interceptor means and citadels with the most powerful military means.”

Kim Tae-woo, a missile expert at Seoul’s state-run Korea Institute for Defense Analyses, said a recent commercial image shows a round-shaped top on the North’s rocket, possibly suggesting it could be a satellite as Pyongyang claims. But he stressed the object could be designed to disguise a missile test.

“It was not shaped like a warhead,” Kim said. “But the North can put anything atop the rocket for a missile test as long as it weighs the same as a warhead.”

Two US destroyers are believed to have departed from South Korea to monitor the rocket launch.

The latest announcement comes a day after the North announced it will indict and try two American journalists accused of crossing the border illegally from China on March 17 and engaging in “hostile acts.”