Local authorities reported that the accident occurred on the Vinh Hao-Phan Thiet Expressway at around 1 am. A passenger bus carrying 32 people had to stop on the roadside after the driver noticed some problems. There was no emergency lane on the expressway when another passenger bus, carrying 25 people running in the same direction, crashed into the stationary vehicle.

The intense crash left two passengers on the second bus dead on the spot. Four others suffered serious injuries and were sent to a local hospital for treatment.

Following the collision, the two buses were badly damaged, and a 15-metre section of the road's fence was also broken.

Police are further investigating the cause of the accident.

Opened in May last year, the Vinh Hao-Phan Thiet Expressway spans 100 kilometres in Binh Thuan Province. The expressway allows the highest speed of 90 km per hour, but no emergency lane exists.