HARBIN - The death toll from a van blast in Northeast China's Heilongjiang province rose to 11 after four injured people died in hospitals despite treatment, local authorities said Saturday.

Both the commuter bus belonging to a mining company and another affected passenger bus had casualties, said a statement of the Shuangyashan city government.

The commuter-van from Zhongxing Mineral Industry Company exploded around 6:30 am Friday in the city's Lingdong district. The explosion affected a coach on the opposite lane.

Seven of the 52 passengers aboard the two vehicles were killed at the scene. Another 40 were injured and rushed to two local hospitals for treatment.

An initial investigation by the experts from the Ministry of Public Security showed that there might be explosives on the vehicle at the time of blast, the city government said. Further investigation is still going on.