Three soldiers were killed and three others wounded on Thursday when suspected militants ambushed an army convoy in Arunachal Pradesh's Tirap district.
Six army personnel in the convoy were injured in heavy firing by the militants, an army official said, adding that three soldiers later succumbed to their injuries.
"The army convoy was on its way to Longding district in Arunachal Pradesh from an army base in Assam's Tinsukia district. When the convoy reached Topi area, a group of suspected militants started indiscriminate firing," the official said.
"We suspect the role of NSCN-Khaplang faction behind the attack. The NSCN faction must have taken the help of anti-talk faction of ULFA militants in carrying out the ambush," he said.
The official, however, added that the role of National Socialist Council of Nagaland-Isak Muivah (NSCN-IM) could not be ruled out.
On Friday, NSCN-Khaplang led by S.S. Khaplang abrogated the ceasefire agreement with the central government.
Tirap and Changlang districts of Arunachal Pradesh, that borders Myanmar, have been a stronghold of the NSCN factions and the route is also frequented by the anti-talk faction of United Liberation Front of Asom to sneak over to Myanmar, where these groups have camps.