NEW DELHI, Dec. 16 (Xinhua) -- At least four people were killed and three others injured Sunday in a boiler blast in a sugar factory in southern Indian state of Karnataka, officials said.

The blast took place at the factory's treatment plant in Mudhol of Bagalkot district, about 554 km north of Bengaluru, the capital city of Karnataka.

"Four labourers were killed and three others severely injured after a boiler blasted in the distillery unit of a sugar factory here this afternoon," an official at Bagalkot said. "The injured have been moved to the hospital."

Reports said the intensity of the blast caused the building to collapse.

Following the blast, police and fire tenders rushed to the spot to carry out rescue work.

Locals said the sound of the blast was heard in the entire village.

Murugesh Nirani, the owner of the factory, told local media the explosion occurred in the treatment plant which is about half a kilometre from the main factory.

"The blast occurred in a treatment plant about half a kilometer away from the factory where seven people were working today. Three died on the spot, one in the hospital and three are being treated at the hospital," Nirani said.

On Thursday, three people were killed and few others injured in a boiler blast inside a steel factory in federally governed western India's territory of Dadra and Nagar Haveli.