By Agence France-Presse Thousands of people joined fresh rallies against a contentious citizenship law in India on Saturday, with 21 killed so far in this month's unrest. (AFP) The death toll jumped after demonstrations turned violent on Friday in the most populous state Uttar Pradesh, leaving at least 11 dead including an eight-year-old boy, who was trampled. Another protester died Saturday after clashes in Rampur, also in Uttar Pradesh, as police used tear gas and batons against a stone-pelting crowd, police told AFP. Disquiet has been growing about the law, which was passed by parliament on December 11 and gives people from persecuted minorities from three neighboring 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 has denied. Authorities have scrambled to contain the situation -- imposing emergency laws, blocking internet access, and shutting down shops in sensitive areas across the country. Demonstrators have vowed to keep up their fight until the law is revoked. Protests were held Saturday in numerous states, including in the cities of Chennai, Gurgaon and Guwahati. As day broke in the capital New Delhi, demonstrators held up their mobile phones as torches at India's biggest mosque Jama Masjid in a show of dissent. In Patna in the eastern state of Bihar, three demonstrators suffered bullet wounds and six were hurt from stone-pelting after clashing with counter-protesters, police said. At an all-women protest in Assam state's Guwahati city in the northeast -- 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. The BJP has said it wants to conduct the National Register of Citizens (NRC) nationwide, fueling fears Muslims -- a 200-million minority in India -- were being disenfranchised. BJP's general secretary Bhupender Yadav told reporters Saturday the party would "launch an awareness campaign" and hold 1,000 rallies to dispel "lies" about the law. In northern Uttar Pradesh, Muslims make up almost 20 percent of the 200-million population. The state's police spokesman Shirish Chandra told AFP 10 people died Friday after being shot. The boy also died Friday in a "stampede-like situation" when 2,500 people including children joined a rally in the holy city of Varanasi, district police chief Prabhakar Chaudhary told AFP. The unrest had already seen one death in Uttar Pradesh, two in the southwestern state of Karnataka and six in Assam. On Saturday police erected 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 on Friday evening in Delhi with police firing a water cannon and baton-charging protesters, who chanted anti-Modi slogans and threw stones. An AFP reporter at the scene saw protesters, including children, being detained and beaten by police. 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 were arrested over charges of violence, the police spokesman added. Delhi's chief metropolitan magistrate late Friday had ordered the release of everyone under 18 who was detained. 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 added. On Saturday, distraught families and lawyers waited outside a police station in Old Delhi where nearly dozen people were being held.