Three people have died during new clashes between demonstrators and police in northern India, raising the nationwide death toll in protests against a new citizenship law to 17.

OP Singh, the chief of police in Uttar Pradesh state, said the latest deaths have increased the toll in the state to nine, adding: “The number of fatalities may increase.”

Police clashed with thousands of protesters who took to the streets again in several parts of the country to oppose the new law, which they say discriminates against Muslims.

The backlash against the law marks the strongest show of dissent against the Hindu nationalist government of prime minister Narendra Modi since he was first elected in 2014.

Narendra Modi
Narendra Modi (Manish Swarup/AP)

The law allows Hindus, Christians and other religious minorities who are in India illegally to become citizens if they can show they were persecuted because of their religion in Muslim-majority Bangladesh, Pakistan and Afghanistan. It does not apply to Muslims.

Critics have condemned the law as a violation of India’s secular constitution and label it the latest effort by the Modi government to marginalise the country’s 200 million Muslims. Mr Modi has defended the law as a humanitarian measure.

Six people were killed during clashes in Uttar Pradesh on Friday, and police said on Saturday that more than 600 in the state had been taken into custody since then as part of “preventive action”.

Police have imposed a British colonial-era law banning the assembly of more than four people in some parts of the state.

The government also issued an advisory on Friday night asking broadcasters across India to refrain from using content that could inflame further violence.

The Ministry of Information and Broadcasting asked for “strict compliance”.

A protest in New Delhi
A protest in New Delhi (Altaf Qadri/AP)

Authorities have stepped up phone and mobile internet shutdowns in some parts of the country in an effort to thwart the protests.

Areas of New Delhi, the eastern state of West Bengal, the northern city of Aligarh and the entire state of Assam have been affected in the days since the law was passed.

In Aligarh, where police beat students and fired tear gas shells inside a university last week, internet services on Saturday were suspended for the sixth straight day. The services were also barred in the capital of Uttar Pradesh.

In the north-eastern border state of Assam, where internet services were restored after a 10-day block, hundreds of women on Saturday staged a sit-in against the law in Gauhati, the state capital.

“Our peaceful protests will continue till this illegal and unconstitutional citizenship law amendment is scrapped,” said Samujjal Bhattacharya, the leader of the All Assam Students Union, which organised the rally.

He rejected an offer for dialogue by Assam chief minister Sarbananda Sonowal.

In New Delhi on Saturday, police charged more than a dozen people with rioting in connection with violence during a protest on Friday night in the Daryaganj area.

Protests against the law come amid an ongoing crackdown in Muslim-majority Kashmir, the Himalayan region stripped of its semi-autonomous status and downgraded from a state into a federal territory in August.

The demonstrations also follow a contentious process in Assam meant to weed out foreigners living in the country illegally. Nearly two million people were excluded from an official list of citizens, about half Hindu and half Muslim, and have been asked to prove their citizenship or be considered foreign.

India is building a detention centre for some of the tens of thousands of people the courts are expected to determine have entered illegally. Mr Modi’s interior minister, Amit Shah, has pledged to roll out the process nationwide.