At least two people have died in clashes with Indian police in the north-eastern state of Assam, officials said.
Police said the two had been caught in crossfire in the city of Guwahati where thousands had ignored a curfew to protest against a new citizenship bill.
Troops have been deployed in parts of Assam and neighbouring Tripura state.
The Citizenship Amendment Bill (CAB) offers amnesty to non-Muslim illegal immigrants from three countries.
Critics across India say the bill is discriminatory. In the north-east, protesters claim they will be “overrun” by migrants from bangladesh.
Prime Minister Narendra Modi has appealed for calm.
The bill – which applies to people from Afghanistan, bangladesh and Pakistan – was passed in the upper house of parliament on Wednesday night. It is yet to be signed by the president, but that is considered a formality.
The ruling Hindu nationalist Bharatiya Janata Party says the CAB will give sanctuary to people fleeing religious persecution.
Illegal migration from Bangladesh has long been a concern in India's north-east. Assam is one of India's most multi-ethnic states and includes Bengali- and Assamese-speaking Hindus and various tribespeople.
A third of its 32 million citizens are Muslims, the second-highest number after…
