The death toll in Delhi's worst religious violence in decades has risen to 20 as Indian police have been accused of looking the other way while Muslims and their properties were targeted.

A mosque was set on fire in the Indian capital on Tuesday by Hindu mobs, as several Muslim populated areas in the city were attacked during three days of violence, which were triggered after attacks on sit-ins against a new citizenship law.

Indian website The Wire reported that a mob shouting "Jai Shri Ram", translated to "hail Lord Ram", paraded around the burning mosque in the Ashok Nagar area of the capital.

Video footage shared on social media showed a mob climbing to the top of the mosque's minaret where they attempted to plant a saffron flag.

Local media reported that shops in the area were also being targeted by the mob. 

Police imposed a restriction on large gatherings in northeast Delhi as reports emerged of stone-pelting and more structures being set ablaze.

Sunil Kumar, Medical Director of Guru Teg Bahadur Hospital, where the injured were taken to, said on Wednesday at a news conference that 20 people have died in the violence, including a policeman.

Another official at the hospital, Rajesh Kalra, told AFP news agency that 31 people, including 10 who were seriously hurt, were admitted earlier on Tuesday.

"Since yesterday, we've been calling the police to enforce a curfew, to send reinforcements," Saurabh Sharma, a student from a riot-hit area who took his injured friend to the hospital, told AFP.

Anil Mittal, a senior police officer, said approximately 150 people were injured in the violence that started as US President Donald Trump arrived on a two-day India trip.

"Some of the people brought in had gunshot wounds," Rajesh Kalra, additional medical superintendent at the Guru Teg Bahadur Hospital, said of Monday's violence.

Fresh violence has been reported from Muslim populated areas such as Karawal Nagar, Maujpur, Bhajanpura, Vijay Park and Yamuna Vihar, while stones were thrown in neighbourhoods such as Maujpur.

Chief Minister of Delhi Arvind Kejriwal appealed to residents to maintain peace after an urgent meeting of his newly elected legislators in the capital.

SOURCE: Al Jazeera and news agencies