Thirteen people have been killed and over 150 injured in clashes between opposing groups of protesters in New Delhi, police said yesterday, as violence over a contentious citizenship law roiled India's capital for a second day.

There have been widespread protests since the law that critics say is anti-Muslim was passed in mid-December, with more than 25 people killed.

The clashes, the worst in the capital since unrest over a new citizenship law began in December, started at the weekend but turned deadly on Monday. Fresh violence erupted in multiple areas of northeast Delhi yesterday.

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 12 civilians and one policeman are confirmed dead, reports AFP quoting a police officer, adding that more than 150 people had been injured since Monday.