HARBIN - Seven people were killed and more than 20 others injured after a commuter-van exploded in Northeast China's Heilongjiang province on Friday, local authorities said.

The commuter-van from Zhongxing Mineral Industry Company in Shuangyashan City exploded around 6:30 am in the district of Lingdong, the Shuangyashan city government said in a statement.

It is not known how many people were on the vehicle when the accident happened.

The explosion affected a mini-van on the opposite lane. A previous report said a collision between the commuter-van and the mini-van led to the explosion, which proved to be inaccurate.

The injured have been sent to two hospitals. Their conditions are not available.

An investigation into the cause of the accident is under way.