Thousands of soldiers have fanned out across the Indian state of Assam, looking for rebels who have killed at least 70 people since the weekend.
Additional forces are being sent to Assam
Military officials say 2,000 more soldiers are on stand-by.
Indian defence minister AK Antony and army chief General JJ Singh have arrived in the state to assess what can be done.
In the continuing violence, two more Hindi-speaking migrants have been killed in a late-night attack.
Authorities blame the attacks on the United Liberation Front of Assam (Ulfa) rebels, who are fighting for an independent homeland.
Military officials say 13,000 soldiers and paramilitary troops are scouring wide stretches of forest and mountainous terrain along the state's northern border with Arunachal Pradesh state.
They say two rebels were killed by the soldiers in an encounter on Tuesday morning at Moran, in Sibsagar district.
Thousands of migrants are fleeing Assam
"The joint offensive by security forces of both Assam and Arunachal Pradesh will track down Ulfa rebels believed to be taking shelter here," Arunachal Pradesh police chief Amod Kanth was quoted by news agency AFP as saying.
Officials say Ulfa rebels have some bases in the neighbouring state of Arunachal Pradesh which they use for hiding after carrying out attacks and also as a transit point to their bases elsewhere.
The latest series of violent attacks have all targeted Hindi-speaking migrant settlers in Assam, mostly from the eastern state of Bihar.
Many of those killed in the state's worst violence in a decade have been impoverished brick factory workers.
Thousands of Hindi-speaking migrants are now fleeing in fear of the attacks.
The settlers have been visited by India's junior Home Minister, Sriprakash Jaiswal, and the Railway Minister, Laloo Prasad Yadav.
They have both tried to reassure the Hindi-speaking settlers and promised to crush Ulfa rebels.
But there do not seem to be many takers for their assurances. All across the violence-affected districts of Assam, railway stations are crowded with thousands waiting to catch the next train out of the state.
Assam police officials say the rebels may further intensify their violent campaign ahead of India's Republic Day celebrations later this month (on 26 January) and the Indian National Games, scheduled to be held in Assam in February.
The rebels say India's central government exploits the state's rich resources such as tea and natural gas and does little for its people who are ethnically closer to Burma and China than to India.