Nice (France) (AFP) - Police were hunting three arson suspects on Thursday after an apartment building fire killed seven people including four children in the southern French city of Nice, Prime Minister Gabriel Attal said.

The victims – all members of a family of Comoran origin – included three adults and children aged five, seven and 10, as well as a 17-year-old who tried to escape by jumping from a window, authorities said.

Three other family members survived the blaze by jumping from windows.

Their seventh-floor apartment is located in the low-income neighbourhood of Les Moulins, known for being a drug-dealing hub, in the west of the city.

“What happened here, this fire, is absolutely awful and revolting,” Attal told reporters at the scene.

“The investigation is ongoing, three individuals are being sought”.

Nice Deputy Mayor Anthony Borre had said earlier that surveillance footage showed three men wearing balaclavas in the vicinity.

The apartment was occupied by a family believed to have Comoran origins, regional prefect Hugues Moutouh said, referring to the Comoros island nation located off the eastern coast of Africa.

Ten people were inside when the fire broke out and rescuers were alerted at around 2:30 am (0030 GMT) to the blaze on the seventh and top floor of the building.

But despite the resources deployed, seven of the family members lost their lives, Moutouh said.

A 47-year-old who also jumped out of a window was severely injured, he said.

Neighbours had hurriedly dragged mattresses in front of the building to break the fall of those jumping out of windows, witnesses said.

Members of the Comoran community said the two other survivors were a 17-year-old, whose twin died, and his 19-year-old brother.

“They are devastated,” said Nadjim Maecha, the head of a local Comoran solidarity organisation.

President Emmanuel Macron on social media said his thoughts were “with the loved ones of those who died”.

- ‘Still hear the cries’ -

Nice prosecutor Damien Martinelli said in the evening that so far the probe seemed to confirm a “criminal” cause for the fire, with fires starting on the first, second and third floors.

He said that investigators were looking into the possibility of “a feud in a context of drug trafficking, not linked to the victims and their families”.

Borre, Nice’s deputy mayor, called what happened “barbaric”.

Arriving firefighters were confronted by a “raging apartment fire” on the seventh floor of the building.

They carried out three aerial ladder rescues and evacuated dozens.

“There were flames in the staircase and smoke was entering under the door,” said Soibrata, a resident on the building’s fifth floor.

“I woke the children up, and called the firefighters who told us to put wet towels under the doors and go on the balcony” where they were rescued, she said.

Soibrata, who did not give her last name, and others in the building told AFP that the wait for firefighters had been much longer than the “10 minutes” Martinelli said it took for them to arrive.

Neighbours sprayed water on parasols and furniture on adjacent balconies to prevent falling burning debris from setting the rest of the building on fire, they said.

Zyad Mohamed, a 23-year-old psychology student who lives in a neighbouring building, said he was “angry and sad”.

“I can still hear the cries from last night,” he said.

Twenty people were evacuated to a temporary shelter, with Nice Mayor Christian Estrosi saying a crisis unit would be set up to help anyone affected by the fire.

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