Forest fire caused by lightning are spreading in virgin forests in north China's Greater Khingan Range, firefighters said Friday.

More than 1,000 police officers are fighting fire in the mountain, a major base for the country's virgin forest reserve.

There are a total of 10 separate flame spots that are expanding to larger areas, according to the police.

Lasting high temperature and aridity since late May posed great fire risk. Continued lightning that began in mid June stroke dry, withered trees and caused fire, police said.

Helicopters were employed to send firefighters to the fire sites which are mostly located in the far inland of dense woods.

An additional 400 police officers were mobilized Friday morning and would be sent to join in extinguishing efforts later in the day, police said.

(Xinhua News Agency June 25, 2004)