At least 10 tribal separatists were killed and a paramilitary commander was wounded in two separate attacks in the northeastern states of Manipur and Nagaland, officials said on Wednesday.
A defence spokesman said paramilitary Assam Rifles troopers on Tuesday killed four militants of the outlawed Kuki National Front (KNF) in an encounter near Thonglan village in Manipur's Senapati district.
"We were tipped off by locals that a group of rebels were moving in the area and trying to carry out extortions.
"The encounter lasted for a couple of hours and we managed to eliminate four KNF militants and recovered one light machine gun, an M-16 rifle, and other weapons and ammunition from the victims," said defence spokesman Rajesh Mishra.
A paramilitary commander was wounded in the encounter, he added.
The KNF is a rebel group fighting for an independent homeland for the minority Kuki tribe in Manipur, a state bordering Myanmar.
Kuki militants killed six people belonging to the majority Metei community in Manipur over the weekend, triggering violent clashes that prompted authorities to enforce an indefinite curfew and issue shoot-on-sight orders.
In the adjoining Nagaland state, six tribal separatists were killed in fratricidal clashes between two rival guerrilla factions despite a ceasefire with New Delhi.
A police spokesman said heavily armed militants of the Isak-Muivah faction of the National Socialist Council of Nagaland (NSCN-IM) late on Tuesday attacked and killed four cadres of the rival group headed by SS Khaplang (NSCN-Khaplang) in village Mekukla, about 120 km from state capital Kohima.
"Armed NSCN-IM terrorists shot dead four of our cadres without any provocation. There is a ceasefire on and so our cadres took them lightly, but they rained bullets on members of our mobile unit," AZ Jami, a senior NSCN-Khaplang leader, told IANS by telephone.
Two NSCN-IM rebels were killed in retaliatory attacks.
Both the NSCN factions are operating a ceasefire with New Delhi - the NSCN-IM is holding peace talks after the group entered into a truce in 1997. The NSCN (Khaplang) is yet to begin formal talks with New Delhi although the group signed a ceasefire pact with the Centre in 2001.
"The attacks are nothing but gross violation of the ceasefire ground rules," Jami said.
The two warring factions are engaged in a bitter fratricidal war for territorial supremacy with at least 200 cadres killed during the past five years. The northeast is home to over 30 rebel groups with demands ranging from independence to greater autonomy and the right to self-determination.