HARBIN - A forest fire that broke out Saturday morning is quickly spreading in Northeast China's Heilongjiang province, local firefighters said.

The fire was spotted around 10 am in Sunwu county of Heihe city, and as of 3 pm has raged through 7.7 square kilometers due to strong winds, according to the city's firefighting authorities.

No casualties or property losses have been reported so far.

Local authorities have dispatched 906 soldiers and firefighters to the site, and an investigation into the cause of the fire is under way.