"According to unconfirmed information, the missile is believed to have only flown for an extremely short distance," a government official said.

"We do not think it would affect our country's security even if it is true that the missile was fired," said the official who declined to be named.

The US government said North Korea apparently fired a short-range missile into the Sea of Japan on Sunday and called on its allies to express concern to the nuclear-armed Stalinist country.

North Korea rattled its neighbours in 1998 by test-firing a Taepodong-1 long range missile over Japan and into the Pacific Ocean. It has carried out other tests of short range missiles since then.

The latest North Korean action could heighten concerns about its intentions as it continues to boycott six-nation talks on its nuclear arms program.

Japan is engaged in a separate row with North Korea over its past kidnappings of Japanese citizens. Prime Minister Junichiro Koizumi has tried to engage the Stalinist state, travelling twice to Pyongyang for summits.

Japanese broadcaster NHK said the missile was fired from the east coast of North Korea and flew about 100 kilometers (62 miles) until it fell into the sea. The United States informed Japan and South Korea after monitoring the launch of the missile, reports said.

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