The eastern part of the country, where movements against Bangladeshi immigrants have raged for decades, has been among the worst hit by the demonstrations.
Protests against a divisive new citizenship law raged Saturday as Washington and London issued travel warnings for northeast India following days of violent clashes that have killed two people so far.
Many in the far-flung, resource-rich region fear the new legislation will grant citizenship to large numbers of immigrants from neighbouring Bangladesh, whom they accuse of stealing jobs and diluting the region's cultural identity.
Hundreds of protesters rallied in the capital, New Delhi, on Saturday, urging Prime Minister Narendra Modi's government to revoke the law that they said would "divide our secular country on religious lines".
Protests took a violent turn in West Bengal state, where a portion of a railway station complex was set on fire. Burning tyres were thrown on rail tracks and key roads blocked by slogan-chanting protesters.
Tensions simmered in Guwahati in Assam state, the epicentre of the unrest, where medical staff said two people were shot dead and 26 hospitalised late Thursday after security forces fired live rounds.
Friday's funeral procession of 18-year-old Sam Stafford, who was killed in the firing, was attended by hundreds of angry and distraught mourners who shouted, "long live Assam".
"We were watching news all day on TV about the protests when my nephew left home in the evening. We asked him not to go but he went with his friends," the student's aunt Julie Stafford said.
Anticipating further unrest, authorities extended an internet ban across Assam till Monday. Most shops were shut and anxious residents stocked up supplies Saturday when the curfew was relaxed during the day.
The Citizenship Amendment Bill – approved this week – allows for the fast-tracking of applications from religious minorities from Pakistan, Afghanistan and Bangladesh, but not Muslims.
For Islamic groups, the opposition and rights organisations, it is part of Modi's Hindu nationalist agenda to marginalise India's 200 million Muslims.
Modi denies this and says that Muslims from the three countries are not covered by the legislation because they have no need of India's protection.
The US State Department on Thursday urged India to "protect the rights of its religious minorities", according to Bloomberg.
The UN human rights office said it was concerned the law "would appear to undermine the commitment to equality before the law enshrined in India's constitution".
But many in the northeast object for different reasons, fearing that immigrants from Bangladesh – many of them Hindus – will become citizens, taking jobs and diluting the area's cultural identity.
The passage of the law sparked angry scenes in both houses of parliament this week, with one lawmaker likening it to anti-Jewish legislation by the Nazis in 1930s Germany.
Rahul Gandhi of the opposition Congress party has called the law "an attempt to ethnically cleanse the northeast".
The chief ministers of several Indian states – West Bengal, Punjab, Kerala, Madhya Pradesh and Chhattisgarh – have said they will not implement the law.
West Bengal's firebrand leader Mamata Banerjee, who has called for major protests in state capital Kolkata on Monday, said Modi wanted to "divide the nation".
"It is completely unconstitutional and goes against the idea of India," Aditya Mukherjee, a professor at Jawaharlal Nehru University, told the NDTV channel.