Three triplets from New Zealand were among the 13 children killed when fire swept through a shopping centre in Doha, according to Prime Minister John Key.
Mr Key said the triplets, believed to be three-year-olds, were in a nursery in the Villagio mall in the Qatari capital when the fire broke out.
Radio New Zealand has named them as Lillie, Jackson and Willsher Weekes.
Altogether 19 people died in the blaze. The child victims - seven girls and six boys - were aged one to three. All were foreign and included European and Japanese.
One Spanish family is also said to gave lost three children.
Local journalists who attended an official news conference told Sky News the youngsters were trapped in the day care centre for more than two hours.
Four of the adult casualties were female teachers at the nursery, the other two were firefighters.
Mr Key said the triplets' parents were New Zealanders who had been working in the country for some time.
"It's a great tragedy," he told reporters. "Their family are obviously dealing with the terrible grief that they have at this time. Obviously it's a very tragic day for that family."
The children's grandparents were reportedly flying to Qatar to support the family. New Zealand consular officials were also offering assistance.
New Zealand journalist Tarek Bazley said he was in the shopping centre with his two children when the fire started. Luckily they escaped unharmed.
"The volume of smoke coming out of it, it looked like you had 30 steam trains all pumping their smoke out above it," Mr Bazley told Radio New Zealand.
He said there was a lack of urgency from officials in the mall when alarms went off and complained of a "complete lack of planning, a complete lack of coordination in terms of removing people from this area".
"The first thing I heard of it was a very benign fire alarm, it sounded more like a door bell to be honest," he said.
"After about 15 minutes I asked the attendant on the soft play area, where I was with my children, whether that was something we should be worried about, he said 'no sit tight, it's usually a false alarm'.
"About 10 minutes later someone else, a member of the public raced through this area and said 'everybody out, you've got to get out now, the other half of the mall is on fire'."
Brian Candy, a photographer who took pictures at the scene, told Sky News: "There were more emergency services than I've ever seen in my life in attendance... air ambulances coming and going.
"There was a lot of noise... noise of emergency services people shouting instructions, what sounded like women crying, wailing in fact. Truly, a very sad and disturbing sight."
Qatari officials said the blaze started in the nursery and firefighters had to break through the roof to get to children who were trapped after a staircase to the first-floor facility collapsed.
Thick black smoke was seen billowing from the building at the height of the fire, which broke out at about 11am local time.
Some 17 people, including two children, were taken to hospital suffering from smoke inhalation.
Many of those in the shopping centre when the alarm was raised were helped out through the roof.
The Italian-themed Villaggio, one of the biggest shopping centres in Qatar, opened in 2006 and has 220 stores as well as a funfair and ice-skating rink.
There are many ex-patriates in the oil-rich Gulf Arab state, which has one of the highest standards of living in the world.