A new satellite image shows a marked increase in activity at a missile launch site of the Democratic People's Republic of Korea, pointing to a possible long-range ballistic missile test by Pyongyang in the next three weeks.

The imagery taken by satellite operator DigitalGlobe Inc was released days after Japanese newspaper Asahi Shimbun reported that US intelligence analysts had detected moves that were seen as preparation by the DPRK for a long-range missile launch as early as this month.

DigitalGlobe, which provides commercial satellite imagery to the US government and foreign governments, on Monday released the image that it said was at the DPRK's Sohae Satellite Launch Station.