This article is more than 9 years old

This article is more than 9 years old

South Korean officials said today there have been continual movements of personnel and vehicles at North Korea's main nuclear test site, but ruled out the possibility that the country is preparing its third atomic bomb test soon.

The assessment came shortly after the Chosun Ilbo newspaper reported today that Pyongyang may be preparing another nuclear test, citing "brisk" activities at its atomic test site in the north-eastern county of Kilju.

The paper, citing an unidentified South Korean government source, said a US spy satellite had detected increased activity and that North Korea could detonate a nuclear device within three months.

The North may have intentionally let movements be detected by the US and South Korean authorities to force them to soften hardline policies and to wrest concessions and aid, the paper said. North Korea may also be preparing a bomb test to bolster its military capability amid moves to transfer power from leader Kim Jong-il to his third and youngest son, Kim Jong-un, it said.

However, South Korean officials denied the North was preparing a nuclear test soon, saying continual personnel and vehicle movements have been detected for more than a year at the site, where the North has conducted two bomb tests in recent years.

One official, speaking anonymously, said the movements at the site could be seen as maintenance. Another, from the defence ministry, noted that South Korean and US authorities have been keeping a close watch on North Korean nuclear facilities.

The US military command in Seoul said today it could not comment on the Chosun Ilbo report.

North Korea carried out its first nuclear test in 2006 and a second, more powerful test blast last year, inviting widespread international sanctions.

The country last year walked out of six-nation disarmament talks on its nuclear programme to protest against international condemnation of its prohibited long-range rocket launch. The country has recently expressed its willingness to rejoin the talks – involving the two Koreas, the US, China, Russia and Japan.

"Chances for North Korea doing a third nuclear test aren't high," said Kim Yong-hyun, an expert on North Korea at Seoul's Dongguk University.

Such a provocation "would be too much of a burden" for the impoverished country, which urgently needs outside aid as it tries to maintain stability while it undergoes its succession process, Kim said.

Tension on the peninsula increased following March's sinking of a South Korean warship that was blamed on Pyongyang. North Korea flatly denies attacking the vessel and killing 46 sailors and has warned that any punishment would trigger war.

Recently, however, North Korea has made a series of conciliatory gestures including the release of South Korean and American detainees and proposing the resumption of stalled joint projects with South Korea. In return Seoul has offered to send relief aid to flood victims in the North.