A four-storey building in a Paris suburb collapsed after an explosion on Sunday morning, killing 4 people including a child and an elderly woman, emergency teams are still searching the rubble for others.

Paris Building Explosion

Rescuers were still searching for people who could be trapped under the rubble. (Christophe Ena/Associated Press)

About 150 emergency workers were on hand with sniffer dogs trying to find six people unaccounted for, said the prefect of Seine- Saint-Denis, Philippe Galli.

An eight-year-old child died in the building's collapse, and firefighters found an unconscious 80-year-old woman in the debris who died while being taken out, fire department spokesman Gabriel Plus said.

Ten people, four of them seriously wounded, were pulled out of the rubble, he said.

Gas leak likely behind explosion

Interior Minister Bernard Cazeneuve, speaking to reporters at the scene, said the explosion at around 7 a.m. local time appeared to have been caused by a gas leak. 

Paris-explosion

The explosion forced about 10 people from the building. One 80-year-old woman who had been knocked unconscious in the collapse died while being taken out of the rubble (Christophe Ena/Associated Press)

"We should be prudent, because there are investigations ongoing. There is no certainty," he said.

One side of the building in the suburb of Rosny-Sous-Bois was ripped off completely, exposing the interiors of the apartments. Local authorities said the structure itself appeared to conform to building codes.

Local residents who rushed to help in the moments after the blast described a bloody scene.

"We tried to take people out," said Arafet Brahim, who said he and his friends pulled out some children who appeared to be in good shape.

"But we also took bodies out," he said. "Frankly, it was horrible, I don't know how to describe that moment," he said.