Thousands of fire fighters are working to put out a forest fire that broke out in north China's Shanxi Province Friday night, provincial authorities said Saturday.

The fire started at about 9 p.m. in a forest that borders the cities of Jinzhong and Yangquan. More than 2,600 fire fighters had been mobilized to put out the fire, according to a statement from the Shanxi Forest Fire Prevention Headquarters.

The fire engulfed mainly uninhabited mountains of shrubs, wild grass and some stretches of Chinese pine trees. It currently poses no threat to densely populated villages or important facilities, according to the statement.

No casualties have been reported as of Saturday noon. Local authorities are investigating the cause of the fire.