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

O.P. Singh, the chief of police in Uttar Pradesh state, said the latest deaths increased the death toll in the state to nine since Friday, when police clashed with thousands of protesters who took to the streets in several parts of the country to oppose the new law, which they say discriminates against Muslims.

"The number of fatalities may increase," Singh said. He did not give further details on the latest deaths.

An 8-year-old boy who was trampled was among the fatalities in Uttar Pradesh, India's most populous state where Muslims make up almost 20% of the 200-million population.

The state's police spokesman Shirish Chandra told AFP that 10 people had died Friday after being shot. "All of them were bullet fatalities. We are looking into other cases," he said.

The boy also died Friday after 2,500 people including children joined a rally in the holy city of Varanasi, district police chief Prabhakar Chaudhary told AFP.

"When the police tried to quell the protests, the people ran for cover and a stampede-like situation emerged, in which this boy died," Chaudhary said.

He added that police "exercised complete restraint against the crowds that engaged in attacking them with stones."

The Times of India said the boy was playing in a lane with a friend when they were trampled by a crowd being chased by police.

The ongoing 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.

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 slammed the law as a violation of India's secular constitution and have called it the latest effort by the Modi government to marginalize the country's 200 million Muslims. Modi has defended the law as a humanitarian gesture.

Police said Saturday that over 600 in the Uttar Pradesh 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.

India's Ministry of Information and Broadcasting issued an advisory Friday night asking broadcasters across the country to refrain from using content that could inflame further violence. The ministry asked for "strict compliance."

In the northeastern border state of Assam, where internet services were restored after a 10-day blockade, 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 organized the rally.

He rejected an offer for dialogue by Assam Chief Minister Sarbananda Sonowal, saying talks cannot take place when the "government was hoping to strike some compromise."

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

The unrest has also seen one other death in Uttar Pradesh and two in the southwestern state of Karnataka, while in the Assam state in the northeast – where the wave of protests began last week – six people have been killed and dozens injured.

On Saturday more protests began in cities including Chennai, the capital of the southern Tamil Nadu state, and Patna in eastern Bihar state.

Malaysian Prime Minister Mahathir Mohamad, meanwhile, criticized the law as unfair.

At a news conference following the conclusion of an Islamic summit in Kuala Lumpur, Mahathir said Saturday that India is a secular state and the religions of people should not prevent them from attaining citizenship.

"To exclude Muslims from becoming citizens, even by due process, I think is unfair," he said.

Protests against the law come amid an ongoing crackdown in Muslim-majority Kashmir, the restive Himalayan region stripped of its semi-autonomous status and demoted 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 2 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 else be considered foreign.

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

On Saturday police erected barricades along Jantar Mantar in central Delhi, an avenue that has emerged in recent years as a hotspot for protests.

Authorities have scrambled to contain the situation – imposing emergency laws, blocking internet access and shutting down shops and restaurants in sensitive pockets across the country.

Police have opened fire during the protests, launched tear gas canisters, charged protesters with batons and detained hundreds of people across the vast nation amid the violence.

But demonstrators have vowed to keep up their fight until the law is revoked.

On Friday evening, street battles broke out in the heart of India's capital with police firing a water cannon and baton-charging protesters, who chanted anti-Modi slogans and threw stones, at Delhi Gate in the Old Delhi district.

An AFP reporter at the scene saw protesters, including children, being detained and beaten by police.

In total, 40 protesters were taken into custody, including eight people under the age of 18, police told AFP Saturday, adding that most of them, including the children, were released.

In addition, 15 others were arrested and expected to face charges over the violence, the police spokesman added.

Delhi's chief metropolitan magistrate late Friday had ordered the release of everyone under 18 who was detained.