Triplets from New Zealand were among the 13 children killed when fire swept through a shopping centre in Doha.
The two-year-olds were in a nursery in the Villaggio mall in the Qatari capital when the fire broke out. They were named 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.
As well as the New Zealanders the dead included four Spaniards, a South African boy, an American girl of Arab origin, a Chinese boy, a Canadian girl and an Egyptian girl and boy.
Three of the Spaniards killed were reportedly brothers from one family.
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, three of whom were believed to have been from the Philippines. The other two were firefighters.
A statement from the family of the triplets said: "Lillie, Jackson and Willsher came into this world together and were inseparable as siblings, best friends and the joy of our life.
"Tragically they left together after only two short years. A time that was lived to the full everyday with us laughing, playing, waking us at all hours of the night and simply being the sunshine in our world.
"We would like to thank everyone for their love and support. Our thoughts are also with the other families affected by this tragedy."
Mother Jane Weekes, had lived in Qatar for about five years, although she had returned to New Zealand to give birth to the triplets.
The father, Martin Weekes, is listed on his LinkedIn networking site as a senior adviser at Qatar Media Services and a former chief executive of Auckland's Eden Park sports stadium.
The children's grandparents were reportedly flying to Qatar to support the family.
Grandmother Jo Turner told Fairfax Media. "Our daughter rang. What can you say? It's absolutely devastating. They were everything to her. She was a great mum. She was a hands-on mum."
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.
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."
Thick black smoke was seen billowing from the building at the height of the fire, which broke out at about 11am local time.
New Zealand journalist Tarek Bazley said he was in the Villaggio shopping centre with his two children when the fire started. Luckily they escaped unharmed.
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'."
The interior ministry acknowledged that malfunctioning sprinkler systems and a lack of plans of the building hampered the rescue operation. It said a special committee would now be set up monitor whether safety standards are being followed.
Some 17 people, including two children, were taken to hospital suffering from smoke inhalation.
The Italian-themed Villaggio, one of the biggest shopping malls in Qatar, opened in 2006 and has 220 stores as well as a funfair and ice-skating rink.
It has been closed indefinitely following the blaze.
New construction projects such as the Villaggio have transformed Doha in recent years, as the country has benefitted from huge gas and oil reserves. The shopping centre is close to one of the venues for the 2022 World Cup .
There are many expatriates in the oil-rich Gulf Arab state, which has one of the highest standards of living in the world.