At least four people died and 39 others were injured after a passenger bus overturned on a national highway section in the central province of Ninh Thuan early Monday.

The bus overturned at around 1 a.m. on the section of National Highway 1A in Thuan Nam District, probable because of slippery road as it was raining at that time, police said.

The driver may have lost control of the bus after he made a sharp turn, Nguoi Lao Dong newspaper quoted district police as saying.

The bus was thrown out of the highway and dragged more than 50 meters away. Two passengers died on the spot; two died on the way to hospital.

The 39 injured passengers are being treated at the Ninh Thuan General Hospital.

The bus driver fled the scene after the accident.

The identities of the dead and injured people are not yet confirmed.