A sateliite operator says new images show increased activity at a North Korean launch site, suggesting a long-range missile test could take place in just weeks.

The image released Monday by DigitalGlobe shows an increased level of personnel, trucks and other equipment at North Korea's Sohae (West Sea) Satellite Launch Station.

DigitalGlobe says if North Korea desires, it could carry out a long-range ballistic missile test in the next three weeks. It says the activity is similar to preparations seen before North Korea's failed rocket launch in April.

Nuclear-armed North Korea said the April launch was meant to place a satellite into orbit. But the U.S. and its allies said it was a disguised ballistic missile test banned under U.N. sanctions.

Though recent test launches have failed, Pyongyang is thought to be developing an inter-continental ballistic missile with the aim of being able to strike the United States.

The new launch site activity comes as South Korea is preparing for a December 19 presidential election. Many have thought that Pyongyang will try to influence the outcome of the election by waging a propaganda attack or conducting a missile launch.

North Korean state media have threatened a “sacred war” against the conservative government of South Korean President Lee Myung-bak, who has taken a tough stance against Pyongyang.