LAN SAK, Thailand, Oct 3, 2024 (BSS/AFP) - Weeping parents laid flowers and toys on the coffins of 20 children killed in a Thai school bus inferno, along with three teachers, as five days of funeral prayers began on Thursday.

Family members dressed in black gathered in the assembly hall of Wat Khao Phraya Sangkharam school in the northern province of Uthai Thani to console one another and pray for their loved ones.

A huge display of white flowers adorned the 23 coffins, which were topped with portraits of the dead and offerings of food, drink -- and even toy trucks and dolls -- to comfort the departed spirits.

Most relatives were too traumatised to speak to reporters, but one grandmother choked back sobs to tell of her pain. 

"Their father went to work and left the boys with me, and he was to get them in the evening. I lost both of my grandsons," she told local broadcaster Amarin TV.

Nattawin Tongyoy, a journalist for Thairath TV station, lost a cousin in the blaze.

"I am a reporter, I never think that this kind of news will happen to my cousin one day," he told Thairath. 

"They were children, there was no way they could have escaped."

Buddhist monks will begin formal funeral prayers on Thursday evening, with King Maha Vajiralongkorn to be represented by the head of Thailand's Privy Council. 

The prayers will go on until a mass cremation expected on Tuesday.

- Safety woes -

Police have arrested the driver of the bus on suspicion of causing death by careless driving in the crash, which happened on a highway in a northern Bangkok suburb at lunchtime on Tuesday.

They are also investigating whether the compressed gas tanks fuelling the bus played a role in the blaze, which engulfed the vehicle so quickly that barely half of those on board were able to escape.

It is thought the bus suffered a burst tyre and then crashed into a highway barrier before erupting into flames.

The government has announced urgent checks on more than 13,000 gas-fuelled buses, although some victims' relatives are demanding a complete prohibition.

"I want gas tanks on all public buses and vans to be banned," one told public broadcaster ThaiPBS, without giving her name.

Thailand has long had an appalling road safety record, with around 20,000 deaths reported every year -- an average of more than 50 a day. 

Speeding, drink driving and poor vehicle standards all contribute to the bloody toll, but weak enforcement of rules, exacerbated by rampant corruption in the police, also undermines efforts to improve safety.