At least 20 people were injured when a bus crashed in north China's Heilongjiang Province Thursday, local police said.

The accident occurred at around 2:30 p.m. in Mudanjiang City when a bus veered off No. 201 highway and crashed into a ditch.

Thirty-one people were onboard the bus that was travelling from Linkou County to Mudanjiang City.

The injured were rushed to hospital.

Police are investigating the cause of the accident.