Japanese officials say they have been anticipating for some time a test of the latest-generation North Korean ballistic missile, which could be capable of reaching the United States. But the officials, reacting to reports in the Japanese media, say they do not think a launch is imminent.

Japanese media quoted U.S., Japanese and South Korean government sources Friday as saying there are signs North Korea is preparing to launch its long-range Taepodong-2 ballistic missile.

The reports quote officials as saying large vehicles of the size used to transport missiles have been observed near a suspected launch site in the northeastern part of North Korea.

Japanese Foreign Minister Taro Aso told a parliamentary committee Friday that a launch would be no surprise to Tokyo. Aso says he has been aware for some time that North Korea has been preparing for a possible missile launch.

However, Japanese Defense Agency chief Fukushiro Nukaga says there is no need for alarm. Nukaga says Japan does not believe a launch by the North Koreans is imminent.

A U.S. government official, speaking on condition of anonymity, told VOA the activity near the missile facility could merely be a dry run or a military drill.

North Korea has been developing the multi-stage Taepodong-2 for years, but has never test-fired it. Estimates of its potential range vary from 3,500 to 10,000 kilometers - the latter enough to reach the U.S. mainland.

North Korea says it has developed nuclear weapons to counter a perceived American threat. U.S. intelligence officials have said they believe North Korea may have a few such weapons, but is years away from having the ability to attack the continental United States.

Tokyo and its allies reacted with alarm in August 1998 when North Korea fired a nuclear capable, Taepodong-1 missile over northern Japan.

That missile landed in the Pacific Ocean, and Pyongyang later claimed it was a launch to put a satellite in orbit, but no satellite was deployed.