The factory, a double-storey building in west Delhi's Sudarshan Park area, was used for painting ceiling fans.

Additional Deputy Police Commissioner Sameer Sharma told IANS: "The death toll is now seven. Another person succumbed to his injuries in a hospital."

He said the identity of six of the dead was known. The owner of the factory, Ankit Gupta, was among the injured.

Sharma said a case had been registered against Gupta, a resident of Rohtak in Haryana.

According to the Delhi Fore Service (DFS), which carried out rescue operations, the cause of the deaths were burns and building collapse.

Another police official said a gas cylinder exploded, causing the tragedy.

Eight fire tenders reached the spot and found that due to the impact of the blast the roof and a portion of the building has crashed. A DFS official also said that a blast led to the disaster.

A total of 15 people were rescued from the debris.

On January 20 last year, 17 people died after a fire broke out in an illegal firecracker factory in Delhi's Bawana industrial area.