Hundreds of people have gathered in temples in north-east Thailand, offering candles, toys and prayers while farewelling more than 30 victims of a gun and knife rampage that has shocked the world.

WARNING: Readers may find details in this story distressing.

Children aged between two and five and adults were killed when a man armed with two guns and a knife stormed a Thai daycare centre on Thursday. 

At the Si Uthai temple in the village of Uthai Sawan on Saturday, relatives and family of the victims joined the community to pay their respects. 

They lit candles in front of coffins topped with floral wreaths and framed photographs of the dead. 

One of the coffins belonged to toddler Pattarawat Jamnongnid, whose photo showed him dressed in a pink sports shirt

On his coffin was a model dinosaur and a bottle of milk.

His mother, 40-year-old factory worker Daoreung Jamnongnid, said her only child was energetic and talkative.

At just two years and 10 months, he was the youngest of the children killed but his mother said he already knew the alphabet.

"He was so smart. He liked to watch documentaries with his father," she said. 

Police have identified the attacker as Panya Khamrap, 34, a former police sergeant who was facing trial on a drugs charge.

His autopsy showed no evidence of drug use at the time of his death, according to police. 

Deputy police chief Surachet Hakpan said officers were interviewing 180 people.

Asked about the killer's motive, he said it was "because of his constant stress … his family, his money and his legal cases. So he acted aggressively".

'No words' to describe the tragedy 

Thai Prime Minister Prayuth Chan-ocha has expressed concern about the impact the tragedy will have on the community, according to his spokesperson Anucha Burapachaisri.

"The prime minister asked everyone to support each other and get through this brutal loss together," he said.

Three boys and two girls survived the attack and four of them remain in hospital, police said.

Thailand's King Maha Vajiralongkorn visited the hospital on Friday to express his sorrow over the "evil incident".

"I want to give you all moral support to be strong so that the souls of those children can have a sense of relief that their families will remain strong and be able to move forward."

Meanwhile Kittisak Polprakan, a witness to the attack, described the killing spree.

"It was so quiet," he said.

"There was no noise, no screaming, nothing."

Families farewell loved ones

In front of the daycare centre, people left toy flowers and toy trucks in an offering to the spirits of those killed.

At the Wat Rat Samakee temple, preparations were being made for funerals, with hundreds of people dressed in black.

Earlier in the day, emotions were intense, with relatives crying as saffron-robed monks chanted.

Villagers sat on carpets with hands clasped in front a series of caskets adorned with flowers and portraits of smiling children.

A large toy sports car was placed on one of the coffins, lined with gold-coloured fabric bearing Buddhist symbols.

A woman who lost two nephews aged three was seen weeping as she knelt, palms pressed against one of their caskets.

A television station live streamed what it said was the killer's cremation at a temple in the neighbouring province of Udon Thani.

Three monks chanted as a woman the network identified as his mother wept in front of a white coffin.

"In the next life, may you be reborn a good person, not evil," the woman said.

Reuters