The mother of a victim standing outside the daycare centre on Friday
Parents gathered outside the centre on Friday morning, weeping and clutching their children's favourite toys.
The attack on Thursday left 37 people, including 23 children dead. The perpetrator was an ex-policeman.
Flags across Thailand are flying at half-mast as the country grapples with the tragedy.
Police say the 34-year-old attacker killed himself and his family after a manhunt. The motive for the attack is not yet known. But police said the attacker was fired from his job in June for drug use.
Prime Minister Prayuth Chan-ocha, and Thailand's King Maha Vajiralongkorn, together with the Queen, are expected to visit the community in Nong Bua Lamphu province later on Friday.
Rescue personnel count coffins carrying victims bodies at the hospital morgue in Udon Thani
Overnight, pink and white coffins adorned with gold, bearing the bodies of the children, were brought to a hospital morgue in Udon Thani and laid out in rows.
Rescue workers had earlier brought the victims' bodies to the police station, where families of the dead had gathered. Distraught relatives had also waited outside the daycare centre well into the night.
Police said the armed attacker broke into the building just after lunch time on Thursday, shooting his way past a teacher and parent outside.
Witnesses said he first shot staff - including a teacher who was eight-months pregnant- before forcing his way past teachers into a room where children were napping.
Police said he stabbed most of his victims before fleeing.
Headteacher Nanticha Panchum told the BBC she had just sent the children off for their nap when she heard gunshots.
Usually the centre looked after 92 children on site but because of poor weather and a bus breakdown, there were only 24 there at the time.
Only one child survived, Ms Nanticha said.
"This is something I never dreamed of… I don't know what to do next. I really can't think of anything at the moment," she told the BBC.
The attacker's son went to the centre but hadn't been attending for a month, she said. He was recognised by one of her colleagues when he burst in.
Soon after news of the attack emerged, Thai Police published an online manhunt appeal - identifying the man as Panya Kamrab, a local man. He was a former officer who had been fired in June for drug use, police later said.
The daycare centre on Friday morning
Officers who rushed to the nursery were confronted with the bodies of adults and children, some of them very young, lying inside and outside the building.
"We found that the perpetrator tried to break in and he mainly used a knife to commit the crime by killing a number of small children," said Police Chief Damrongsak Kittiprapat.
"Then he got out and started killing anyone he met along the way with a gun or the knife until he got home.
"We surrounded the house and then found that he committed suicide in his home."
Police said Kamrab returned home, killing his wife and son before taking his own life.
He had appeared in court the morning of the attack on charges related to the use and possible sale of methamphetamine. He had been due to face a verdict on Friday.
Mass shootings in Thailand are rare, although gun ownership rates are relatively high for the region. Illegal weapons are also common in the south-east Asian country, according to the Reuters news agency.
The nursery attack comes less than a month after an army officer shot dead two of his colleagues at a base in Bangkok.
In 2020 a soldier killed 29 people and injured dozens more in the city of Nakhon Ratchasima.
-- Courtesy of BBC News