Four passengers have died after a bus overturned in Qingyuan Manchu autonomous county, Liaoning province, on Tuesday morning, local police confirmed.

The single-vehicle crash occurred at about 10:40 local time in Dusuhe township, around the 10-kilometer mark of Shuangchang road, according to a statement released by the county's public security bureau.

Emergency services, including police, fire crews and medical teams, were dispatched to the scene to carry out rescue operations. All other injured passengers were taken to the hospital and are reported to be in stable condition.

The bus driver has been detained, and police have ruled out drunk-driving, drug use and overloading as possible causes, the statement said.

An investigation into the incident is currently underway.