BANGALORE, INDIA: A fire in a restaurant early Monday killed five workers who were sleeping inside the building in the southern Indian city of Bangalore, police said.

Police officer M.N. Anucheth said the fire broke after customers left and the sleeping workers were trapped on the ground floor of the Kumbaara Sangha building.

He said the fire has been extinguished but what started it is being investigated.

The restaurant is located in Kalasipalyam district, a busy and congested area in the heart of Bangalore, one of India's key information technology hubs, in southern Karnataka state.

The Press Trust of India news agency said the five were burned to death.

Last month, a massive late-night fire in a restaurant at a Mumbai complex killed 15 people . The fire raised questions about fire safety norms in pubs and restaurants, leading to safety checks in Mumbai and other cities.