At least eight people were killed and six others injured on Friday evening in a blast inside a fireworks factory in northern Indian state of Uttar Pradesh, police said.

The blast was triggered in a stockpile of firecrackers inside a factory at village Rasulpur in Budaun district, about 275 km northwest of Lucknow, the capital city of Uttar Pradesh.

"This evening there was an explosion inside a fireworks factory here, due to which seven people were killed on spot and seven others were injured. However, later on, of the injured one more succumbed taking toll to eight," a senior police official posted in Badaun said.

The injured were admitted at a nearest medical facility.

Locals said the blast damaged the factory and caused cracks in nearby buildings.

Police officials said the factory was a registered unit.

"We are trying to ascertain how the blast triggered," the official said.

Following the incident local administration rushed police, fire brigade officials and disaster management personnel to the spot to carry out rescue work.

Accidental explosions are common at Indian fireworks factories and shops.