Security forces in northeast India found the bodies of nine Muslims on Saturday, raising the death toll to 31 in a spate of attacks by suspected tribal militants as a weeks-long general election re-opens ethnic divisions.
The election has rekindled the question of religious animosity across India with the Hindu nationalist Bharatiya Janata Party (BJP) looking set to win, but the violence in the tea-growing state of Assam stems from friction over migration.
Police said six of the nine Muslims found shot dead were women and children. Security forces rescued three children found nearby hiding in forests close to the border with Bhutan.
"Shoot-on-sight orders are issued to troops deployed in troubled areas," L. R. Bishnoi, inspector general of Assam's police, told Reuters.
Assam has a history of sectarian violence and armed groups fighting for greater autonomy or secession from India.
Police suspect militants from the Bodo tribe were behind the latest attacks in a region where tension between ethnic Bodo people and Muslim settlers has simmered for years.
In 2012, clashes erupted in which dozens of people were killed and 400,000 fled their homes.
Bodo representatives say many of the Muslims in Assam are illegal immigrants from neighbouring Bangladesh who encroach on ancestral Bodo lands.
Soldiers in convoys of trucks mounted with rifles were patrolling on Saturday in Baksa district where some of the attacks took place.
The five-week general election, has exacerbated friction over migration in Assam.
Candidates including prime-ministerial front-runner Narendra Modi of the BJP have called for tighter controls.
Polling in the Bodo region ended on April 24. Residents say it is a tight race between a Bodo and a non-tribal candidate. A policeman was killed on polling day.
"There's heightened tension because of the election," said Ajai Sahni, the executive director of the Institute for Conflict Management in New Delhi, although he said it was too early to be certain about exactly what provoked the attacks.