Four persons were killed and eight injured in a blast that took place apparently when the victims were making bombs Tuesday evening near Rampurhat town in Birbhum district, the police said.

While two persons died on the spot, two others succumbed to their injuries in Rampurhat hospital where the eight injured were admitted.

The condition of some of them was critical, the sources said.

The incident occurred when a group of about 15 persons were making bombs at Bagtui village under Rampurhat police station.