Two or more militants attacked the General Engineering Reserve Force (GREF) camp around 1 AM near LoC in Battal village, sources said.
Militants likely infiltrated from across the border to carry out the terror attack, sources said.
In the attack, three civilians were killed, they said, adding that the victims were working as labourers with GREF.
Troops along with the police have cordoned off the area and a counter operation has started, they said.
A senior police officer said all routes to the area have been plugged and the operation is in full swing.
PTI