A trailer-truck carrying bags of salt crashed into six vehicles on a road in Sa Kaeo’s Ta Phraya district on Tuesday morning, killing four people – one of them a five-month-old baby – and injuring nine others, police said.

Police said the accident happened at around 9am on a hill section of Highway No 348 (Ta Phraya-Buri Ram) in the Chong Khao Tako area and caused severe traffic congestion, prompting officers to direct the traffic flow to Khao Chong Takiew instead.

The trailer-truck, an 18-wheeler, had suffered a brake malfunction while heading down from the mountain and hit six vehicles that were travelling uphill.

One of the hit cars was trapped beneath the truck and caught fire, while the accident caused salt bags to be strewn across the road.

Following the accident, police closed off a section of the road to put out the fire and carry out rescue operations.

Police have yet to identify the victims and the trailer-truck driver.

Highway 348 in Sa Kaeo is normally used as a bypass to avoid traffic congestion from the main northeastern road during long holidays.

The highway is manned by the Burapha task force and is normally closed at night as it runs along the Cambodian border.