At least 18 people died and 23 were injured after a tour bus overturned and fell into a ditch in eastern Thailand on Wednesday.
The accident happened at 4am in the morning when the double-decker bus was descending at the Khao San Pu Tone mountain in Prachinburi province and the brakes failed, the police said.
The bus was carrying 49 passengers, including the driver, on an educational field trip.
"It was a downhill road and the brakes failed, and the driver lost control of the vehicle before it overturned," said Colonel Sophon Phramaneehe, adding that those who died were adults on a study trip.
Visuals of the accident showed a bus lying on its side in a ditch on the roadside as rescue and medical workers arrived at the scene and helped victims near the bus with its undercarriage exposed.
Those injured were rushed to a nearby hospital to receive treatment.
Thai prime minister Paetongtarn Shinawatra expressed her condolences to the victims' families and said an investigation was taking place.
"If it is found that there is a violation of the use of vehicles that do not meet the standards or are involved in reckless use of vehicles, legal action will be taken," she said in a post on X.
"Inspection of vehicles must be safe and pass the specified standards before they are put into use to prevent accidents and reduce losses like this again," she said.
A passenger reportedly said that some of them were sleeping and woke up due to the impact of the accident, causing many people to be thrown into different directions.
Na Di district chief Somjai Phutthasena said some of those hospitalised with serious injuries might not survive.
Road accidents and fatalities are common in Thailand due to weak enforcement of vehicle safety standards and poorly maintained roads. The Southeast Asian nation ranked ninth out of 175 World Health Organisation member countries for road traffic deaths, according to its 2023 report.
Last year, a school bus caught fire due to a gas cylinder leak, killing 23 people, including 16 students.
