Protests against an anti-Muslim 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 northeast fear the new legislation will grant citizenship to large numbers of immigrants from neighboring Bangladesh, whom they accuse of stealing jobs and diluting the region's cultural identity.

Several thousand protesters rallied in the capital New Delhi late Saturday to urge Prime Minister Narendra Modi's government to revoke the law, some holding signs reading: "Stop Dividing India."

"People are not gathered here as Hindus, or Muslims, people are gathered here as citizens of India. We reject this bill that has been brought by the Modi government and we want that equal treatment as is enshrined in our constitution," said protester Amit Baruah, 55, a journalist.

Protests turned violent in West Bengal state, a hotbed of political unrest, with at least 20 buses and parts of two railway stations set on fire as demonstrators blocked roads and set fire to tires. No injuries were reported.

Tensions also simmered in Guwahati in Assam state, the epicenter of the unrest, where medical staff said two people were shot dead and 26 hospitalized late Thursday after security forces fired live rounds.

Anticipating further unrest, authorities extended an internet ban across Assam until Monday. Most shops were shut and anxious residents stocked up on supplies Saturday when the curfew was relaxed during the day.

The Citizenship Amendment Act allows for the fast-tracking of applications from religious minorities including Hindus and Sikhs from Pakistan, Afghanistan and Bangladesh, but not Muslims.

Samujjal Bhattacharya from the All Assam Students Union, which has been at the forefront of the protests, said the group would continue its fight against the new law "in the streets and in the court."

Modi and his Japanese counterpart Shinzo Abe postponed a summit that was reportedly due to be held in Guwahati from Sunday, and the United States and Britain warned their nationals to "exercise caution" if travelling to the wider northeast region.

Modi's right-hand man Amit Shah on Saturday sought to reassure the northeastern states, saying the government would protect their "culture, social identity, language and political rights."

Assam has long been a hotbed of ethnic tensions. In 1983 some 2,000 people, mainly Bengali Muslims, were butchered in what became known as the Nellie massacre.

This year a citizenship registry left off 1.9 million people – many of them Muslims – unable to prove that they or their forebears were in Assam before 1971, leaving them to face possible statelessness.

"There has been this agitation (against) illegal migration from Bangladesh over many years," said Sanjoy Hazarika, a professor at Delhi's Jamia Millia Islamia University.

"They feel that their rights to land, to jobs, and the entire social fabric education, existing social services and so on will be impacted by this."