The incident occurred when the woman, a resident of Bandhgachhi village in Kalna, went to a field to relieve herself, SP SMH Mirza said.
The three dragged her behind a bush and raped her before fleeing.
The woman lodged an FIR with the Kalna police station and two of the three accused were arrested, Mirza said.
The two were identified as Sanjib Tudu and Subodh Hembram.
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