Chandigarh, Aug 21 (IANS) At least five workers of a private paper factory near Malerkotla town in Punjab were killed when a blast took place in the boiler of the unit Saturday, police officials said.

While five workers died instantly, three others were injured in the accident.

Punjab police officials said they were investigating what triggered the boiler blast.

Malerkotla town in Sangrur district is about 150 km from state capital Chandigarh.