A school bus veered off the road killing two Thai pupils and critically injuring nine others.

The vehicle was taking 40 children home when one of its wheels fell into a gap on the shoulder of a rural road in Bueng Kan, northeast Thailand.

The youngsters screamed as the dilapidated bus violently lurched before rolling into a grassy ditch, crushing some of them who fell out of the open windows.

Footage shows the distraught kids crying on the road as they waited for emergency services to arrive.

Police rushed to the scene after receiving a report at 4:30 pm local time on Thursday afternoon August 7.

They found the bus lying on its side, with three pupils still stuck inside.

Rescue teams used a crane to lift the overturned bus as personnel extracted the casualties and placed them on a rescue boards.

Authorities said Rasita Nantamatcha, 16, and Naphong Nakhwan, 14, were killed at the scene while Rattaphum Na Chiang Mai, 15, was rushed to the Seka Hospital where she is currently in the ICU.

Eight pupils suffered minor injuries. Rescue worker Warut Naenudon was also treated after being electrocuted during the operation.

Police Lieutenant Olarn Wongchak, Seka Police Station investigator, said: 'We received a report from the 191 Radio Center about a school bus overturning on the Seka–Natom rural highway at kilometer marker 6, about 600 metres before Ban Huai Khom.

'We coordinated with Theparak Rescue, Sattham Seka Rescue, and Sawang Sriwilai Seka Rescue. At the scene, we found a bus with a Nakhon Phanom license plate, overturned on its left side and crushing the students. We couldn't free them at first, so we used cutting tools, a crane, and a backhoe to lift the bus.'

The bus driver, 64, whose identity was not disclosed by officials, said there were around 40 people onboard during the accident.

He claimed the bus was travelling at around 37.3 mph (60 kph) when he drove over the side of the road.

He said: 'I tried to turn the steering wheel to get back onto the road, but the vehicle skidded toward a tree on the roadside. I swerved to avoid it but the vehicle overturned off the side of the road into a drop around 23 feet (seven metres) deep.'

Authorities said they were investigating the exact cause of the accident.

Thailand has one of the world's worst road safety records. Ministers have set the goal of reducing fatalities from 32.7 deaths per 100,000 people to 12 per 100,000 people by the year 2027.

However, a lack of road safety education in schools along with notoriously easy driving tests, police failures to enforce road laws, and chronic under-investment in infrastructure, all appear to hamper the efforts.