20 have been killed in a large explosion at a firecracker factory in Gurdaspur, a northern state of Punjab.

Rescue teams launched search and rescue operations after the explosion, which shattered the windows and collapsed some walls of nearby buildings.

12 injured have been rescued and moved to Gurunanak Hospital in Amritsar, officials said.

Building of the factory was located in a residential area, which collapsed after the explosion, leaving several trapped under the debris.

An investigation is underway to determine the cause of the explosion.