Indian soldiers in armoured trucks patrolled streets in northeast Assam on Sunday after 33 Muslims were killed in carnage that police blamed on tribal separatists, as tensions remained high.
Thousands of families have fled their homes after separatists went on the rampage in two districts of the restive tea-growing region, shooting dead Muslims including women and children as they slept.
The violence comes during the final stretch of the country's mammoth general election that has seen religious and ethnic tensions flare and in which Hindu nationalist hardliner Narendra Modi was expected to win.
Police have blamed indigenous Bodo tribesmen for the violence on Thursday and Friday evenings in the region where Muslims have migrated from across the border with impoverished Bangladesh.
Police said the death toll rose overnight Saturday to 33 after a child died of her injuries in a hospital in the state's main city of Guwahati.
Assam Chief Minister Tarun Gogoi said those responsible would be punished as security forces including federal soldiers fanned out across Baksa and neighbouring Kokrajhar district to prevent further clashes.
"We are taking stern measures and have so far arrested more than 30 people," Gogoi said.
The victims were Muslim migrants whose community has been locked in staggered land disputes with Bodos in the remote state that borders Bhutan and Bangladesh.
Local media reported Bodos targeted Muslims as punishment for failing to support their candidate at the multi-phased election, but this could not be confirmed. Voting in Assam ended on April 24.
Frontrunner for prime minister Modi, from the Bharatiya Janata Party, said last week illegal immigrants from Bangladesh should pack their bags if he came to power at the polls, whose results are announced on May 16.
On Sunday, Muslims in Baksa were refusing to bury 18 of those killed, in a protest against authorities whom they blame for failing to protect them.
"Right now we are sitting in the open with 18 bodies in front of us," said Lafiqul Islam, president of the All Bengali Muslim Students Union.
"We will continue with our protest and not perform the funeral until and unless the chief minister personally visits the spot," he told AFP in Narayanguri village, some 210 kilometres (130 miles) west of Guwahati.
Police blamed the attacks on the outlawed National Democratic Front of Bodoland, which has been demanding a separate homeland for decades, but the group has denied it was behind the violence.
Seventeen people were killed in clashes in the same region in January and thousands of others fled their homes for fear of further attacks.
In 2012, ethnic clashes in the same area claimed about 100 lives and displaced more than 400,000 people.