Nearly 400 people with criminal records were arrested and 200 crude bombs seized, along with half a dozen improvised pistols, at different places across Birbhum district on Saturday night.

The arrests and the seizures were made during raids by police following two back-to-back explosions in the district last week.

District police chief Shyam Singh said: “We have arrested 399 persons who had several criminal charges against them from different corners of the district with a large number of bombs and firearms. The raids will continue.”

The major seizures of the bombs were made in the Labhpur, Parui and Nanoor police station areas.