Thousands of people joined fresh rallies against a contentious citizenship law in India on Saturday, with 24 killed so far in nearly two weeks of widespread unrest.

The death toll jumped one day after demonstrations turned violent on Friday in India's most populous state, Uttar Pradesh, where at least 15 people were killed including an eight-year-old boy who was trampled to death.

One protester died Saturday after clashes in Rampur, also in Uttar Pradesh, as police armed with batons used tear gas against a stone-pelting crowd, police told AFP.

Anger has been growing over the law, approved by parliament on December 11, which gives religious minority members from three neighbouring countries an easier path to citizenship -- but not if they are Muslim.

Critics say the law discriminates against Muslims and is part of Prime Minister Narendra Modi's Hindu-nationalist agenda, a claim his political party denies.

Angry protests against the citizenship law raged into the night in Kanpur, in the northern Indian state of Uttar Pradesh / © AFP

Authorities have imposed emergency laws, blocked internet access, and shut down shops in sensitive areas across the country in an attempt to contain the unrest.

More than 7,000 people have either been detained under emergency laws or arrested for rioting, according to several state police officials.

Uttar Pradesh police said they have arrested 705 people involved in the protests.

The arrests however have done nothing to stop the spread of demonstrations across the country.

Protests were held Saturday in numerous states, including in the cities of Chennai, Delhi, Gurgaon, Kolkata and Guwahati.

As day broke in the capital New Delhi, demonstrators held up their mobile phones as torches outside India's biggest mosque Jama Masjid in a show of dissent.

Police in Meerut, Uttar Pradesh, take aim at angry crowds demonstrating against the citizenship law / © AFP

In Patna, in the eastern state of Bihar, three demonstrators suffered gunshot wounds and six others were wounded in a stone-throwing clash with counter-protesters, police said.

At an all-women protest in Guwahati, in the northeastern state of Assam -- where the wave of protests started amid fears the immigrants would dilute their local cultures -- participants said it was time to speak up.

"We came out to fight for our motherland, we came to fight without any arms and ammunition, we will fight peacefully," Lily Dutta told AFP.

- 'Stampede-like situation' -

Since being re-elected this year Modi and his Bharatiya Janata Party have stripped Muslim-majority Kashmir of its autonomy and carried out a register of citizens in Assam, a state with a large Muslim population.

Demonstrators have vowed to continue protesting until the citizenship law is revoked / © AFP

The BJP has said it wants to conduct the National Register of Citizens (NRC) nationwide, fuelling fears that Muslims -- a 200-million minority in India -- were being disenfranchised.

BJP's general secretary Bhupender Yadav told reporters Saturday that the party would "launch an awareness campaign" and hold 1,000 rallies to dispel "lies" about the law.

In Uttar Pradesh in northern India, where Muslims make up almost 20 percent of the state's population of 200 million, 15 people were killed in clashes with police, state police chief O.P. Singh said.

One person was killed on Thursday ahead of the Friday's deadly violence that left 14 dead. Another died on Saturday.

Earlier police spokesman Shirish Chandra told AFP 10 people died Friday after being shot.

A boy also died Friday in a "stampede-like situation" when 2,500 people including children joined a rally in the Hindu holy city of Varanasi, district police chief Prabhakar Chaudhary told AFP.

The unrest had already seen two deaths in the southern state of Karnataka and six in northeastern Assam state.

Critics like these women in Chennai say the citizenship law discriminates against Muslims / © AFP

On Saturday police raised barricades along Delhi's Jantar Mantar, an avenue that in recent years has been a hotspot for protests.

It came after street battles broke out in the city late Friday, when protesters throwing stones and chanting anti-Modi slogans clashed with baton-wielding police who deployed a water cannon to disperse the crowd.

An AFP reporter at the scene saw protesters, including children, being detained and beaten by police. More than 45 people were injured in the violence.

Scores of shoes and skull caps were left strewn on the nearly mile-long carriageway that connects the old city with central Delhi after the clashes.

Forty people were taken into custody, including at least eight under 18 years old, police told AFP Saturday, adding that most of them were released. Sixteen others however were arrested on charges of violence, the spokesman said.

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

On Saturday, distraught families and lawyers waited outside a police station in Old Delhi where nearly dozen people were being held.

The leader of a prominent organisation in the Dalit community -- the lowest group in the Hindu caste system -- who joined the Delhi demonstrators was arrested Saturday, police said.