The security personnel were fired upon at around 4 AM and the constable, Pranab Bora, sustained injuries on his hand and left corner of his chest above the bullet-proof vest, district Superintendent of Police M J Mahanta said.
The counter-insurgency operation was being conducted by the police and army personnel.
The army also retaliated and during search operation in the area, one person identified as Debo Fonglo was found dead, the SP said.
Fonglo's son claimed that his father mistaking the security personnel to be miscreants from across Nagaland had fired at them, Mahanta said.