At least 13 people were killed and over 150 injured in clashes between opposing groups of protesters in New Delhi, according to police.
The riots have overshadowed US President Donald Trump's first visit to India.
The clashes, the worst in the capital since unrest over anew citizenship law began in December, started at the weekend but turned deadly yesterday. Fresh violence erupted in multiple areas of northeast Delhi today, just miles away from where Mr Trump and Indian Prime Minister Narendra Modi met for talks.
Local television showed huge clouds of smoke billowing from a tyre market that had been set ablaze. Reuters witnesses saw mobs wielding sticks and stones walking down streets in parts of northeast Delhi and further incidents of stone-throwing.
"At least nine civilians and one policeman are confirmed dead," said Anil Mittal, a police officer, adding that more than150 people had been injured since yesterday.
A fire department official told Reuters that his teams were responding to more than a dozen separate calls relating to arson incidents today, as fresh protests flared around Delhi.
"We have sought police protection as our vehicles are being blocked from entering the affected areas. The situation is very grim," said Delhi Fire Department Director Atul Garg.
He said the violence had not diminished since yesterday despite authorities imposing an emergency measure prohibiting any gatherings in the violence-hit areas.
One fire department vehicle was torched by protesters yesterday and a small number of firemen were injured, Garg added.
"We have about 3,500 police and paramilitary deployed," said Alok Kumar, the joint commissioner of police. "The situation is definitely tense, but we are on top of the situation."
Police fired tear gas and pellets to scatter demonstrators protesting against the citizenship law in the Jafrabad neighbourhood of northeast Delhi. A young man suffered a pellet wound to his thigh, while another sustained injuries to his eyes, leaving his face bloodied.
In New Jafrabad, local residents patrolled the street with sticks and metal rods. Two reporters with the local NDTV news channel were attacked and badly beaten by a mob.
"There is a flow of injured people still coming in. There are casualties," said Dr Rajesh Kalra, the additional medical superintendent at Guru Teg Bahadur Hospital in New Delhi.
"There are all kinds of injuries - many pellet injuries and some from sharp weapons, too," said Kalra, adding some of the injured brought in yesterday had gunshot wounds.
Yesterday police used tear gas and smoke grenades but struggled to disperse stone-throwing crowds who tore down metal barricades and torched vehicles and a petrol pump.
Delhi Chief Minister Arvind Kejriwal appealed for calm.
"Whatever problems people have can be resolved peacefully."Violence will not help find a solution," he said today.
Schools in the northeast of the city were shut today and at least five metro stations closed.
An announcement over a mosque loudspeaker urged protesters to stay non-violent and not attempt to cross police barricades.
"We don't have a problem with the police, we are against the government's law," the male announcer said.
India's capital has been a hotbed of unrest against the Citizenship Amendment Act (CAA), which makes it easier for non-Muslims from three neighbouring Muslim-dominated countries to gain Indian citizenship.
The CAA has sparked accusations that Modi and his Hindu nationalist Bharatiya Janata Party are undermining India's secular traditions. The BJP denies any bias against India's more than 180 million minority Muslims but objectors have staging protests and camping out in parts of New Delhi for two months.
"India is a country that proudly embraces freedom, liberty, individual rights, the rule of law and the dignity of every human being," he told a rally of over 100,000 people in Modi's home state of Gujarat.
"Your unity is an inspiration to the world," he said.