TWO firefighters have been killed and 47 people injured after an apparent gas leak caused an explosion at a bakery in central Paris.

Firefighters pulled injured victims from windows and evacuated residents as smoke billowed over Rue de Trevise in the 9th arrondissement of north-central Paris.

Authorities said 10 people were in a critical condition and 37 others had been less seriously injured.

Interior Minister Christophe Castaner told reporters at the scene “unfortunately the human toll is particularly serious”.

He also paid tribute to rescuers who saved the life of one firefighter who was buried under the rubble for two-and-a-half hours.

Paris Mayor Anne Hidalgo, who was also at the scene, extended a “message of affection and solidarity” to victims.

She said many residents and tourists had been evacuated from neighbouring buildings and hotels.

Paris authorities would help to provide temporary accommodation, the mayor said.

Paris prosecutor Remy Heitz said the explosion’s cause appeared to be an accidental gas leak. He added Paris firefighters were already at the scene to investigate a suspected gas leak at the bakery when the blast took place.

He told reporters “the judicial police have started investigating, the scientific police as well.

He added: “The origin of the explosion seems accidental. We are at the beginning of the investigation everything will be made to establish the exact origin of the explosion as soon as possible.”

Witnesses described hearing the overwhelming sound of the blast and people trapped inside nearby buildings.

Charred debris and broken glass covered the pavement around the apartment building housing the bakery, which resembled a blackened carcass.

Authorities said around 200 firefighters and police were involved in the operation.

A helicopter landed in the area to evacuate the wounded. Silver-helmeted firefighters and red fire trucks filled the street and inspected adjoining courtyards. A vehicle from gas company GRDF was stationed nearby.

Pedro Goncalves, an employee at a hotel by the bakery, said he saw firefighters enter in the morning but he and his co-workers thought it was a false alarm and went back to work. About an hour later, he said a blast rocked the surrounding streets.

“In the middle of nothing, I heard one big explosion and then a lot of pressure came at me [and] a lot of black smoke and glass,” he said. “And I had just enough time to get down and cover myself and protect my head.”

Goncalves said he “felt a lot of things fall on me” and was struck by shattered glass. He had a few cuts on his head, and spots of blood on his sweater and shirt.

“Thank god I’m OK,” he said, saying that the blast was so powerful that he heard whistling in his ears in the aftermath.

Another witness said she had feared it was a terrorist attack.