North Korea, under heavy U.N. sanctions for its nuclear weapons programme, could be preparing a long-range ballistic missile test, a Japanese newspaper said on Friday, citing officials who have seen U.S. intelligence analysis.
The report comes just weeks before South Korea's Dec. 19 presidential election in which how to handle North Korea is a major campaign issue. The isolated North has for years tried to influence major events in the South by waging propaganda or armed attacks.
North and South Korea have been technically at war since their 1950-53 conflict ended in a truce, not a peace treaty, and regional powers have for years been trying to rein in the North's nuclear programme.
"The United States has detected moves that are seen as preparation by North Korea for a long-range missile launch, which could take place as early as this month," the Asahi daily said citing unnamed government officials.
The United States traditionally shares such information with its two allies in the region, South Korea and Japan.
North Korea is believed to be developing a long-range ballistic missile with a range of up to 6,700 km (4,200 miles) aimed at hitting the continental United States but the last two rocket test launches failed.
In April, under its new leader Kim Jong-un, North Korea launched a rocket that flew just a few minutes covering a little over 100 km (60 miles) before crashing into the sea between South Korea and China.
North Korea has said the April launch was aimed at putting a scientific satellite into orbit.
Regional powers trying to stop North Korea's arms programme believe Pyongyang is using rocket launches to perfect technology to build a missile arsenal capable of delivering a nuclear warhead to the United States.
North Korea is under U.N. sanctions that ban trading in missile or nuclear technology that have driven its already dire economy deeper in trouble but cutting off what was once a lucrative source of hard cash.
An official at South Korea's office of the Joint Chiefs of Staff declined to confirm what movements had been detected at the missile site, Tongchang-ri, on North Korea's west coast near China but said it was monitoring developments.