North Korea is preparing for a possible test of an intercontinental ballistic missile with the potential to hit the US, according to Washington officials.

A senior official said there were “enough indications” to suggest that Pyongyang was getting ready to fire a Taepodong-2 missile from a launch pad in eastern North Korea. It would be the Stalinist state’s first test of a longer-range missile since 1998 when Pyongyang generated an international crisis by unexpectedly firing an intermediate-range Taepodong-1 over Japan.

Test preparations are far more advanced than on previous occasions when North Korea appeared to be gearing up for a launch. The Taepodong-2 is a two, or three, stage “integrated” missile. The three-stage version consists of a solid-fuel booster rocket strapped atop a Scud missile attached in turn to a short-range Nodong missile.

The US is monitoring the launch site to see if North Korea starts final assembly of the missile. If North Korea fuelled an assembled Taepodong-2, it would increase the probability of a test, since the move is difficult and dangerous to reverse.

Pyongyang – which is keenly aware that the US can monitor its preparations by satellite – could be bluffing. Kim Jong-Il, the North Korean leader, has a history of performing eye-catching stunts when he feels he is being ignored, which has happened recently as Washington focuses on resolving nuclear tensions with Iran. Another US official said he might be “playing games” to get attention.

While the preparations could be for a satellite launch, the US is positioning military assets to track any launch. In 1998, North Korea claimed that its Taepodong-1 flight was a satellite launch. The senior official said there was no “definitive evidence” that Pyongyang would go ahead with the test.

“We are still not sure that it is ready to launch,” the official said. “This could be a lot of training. It could be political manoeuvring . . . we are not on the edge of our seat yet.”

He added that South Korea was “vigorously” urging China to lobby North Korea to abandon the test. Ban Ki-moon, South Korea’s foreign minister, last week said the preparations were of “great concern” – comments that underscored South Korean anxiety given that Seoul has traditionally played down the chances of any inflammatory actions by the North. The official said the US wanted to avoid creating a crisis because “ that is what North Korea wants”.