As Air Force One flew President Donald Trump and his delegation out of New Delhi late Tuesday, Muslim families huddled in a mosque in a northeast corner of the city, praying Hindu mobs wouldn't burn it down.

The death toll from three days of mob violence rose to 18 on Wednesday, according to a doctor at a hospital where many of the injured were treated, casting a shadow over Trump's flamboyant first state visit to India.

The clashes between Hindu mobs and Muslims protesting a contentious new citizenship law that fast-tracks naturalization for foreign-born religious minorities of all major faiths in South Asia except Islam escalated Tuesday, according to Rouf Khan, 43, a resident of Mustafabad, an area in northeast New Delhi.

Khan said the mobs were wielding iron rods, bricks and bamboo sticks and attacked the homes of Muslims amid chants of "Jai Shri Ram," or "Victory to Lord Ram," the popular Hindu god of the religious epic "Ramayana."

"After forcing inside the homes, they went on a rampage and started beating people and breaking household items," said Khan, adding that he and his family had to run out of fear and take shelter inside a nearby mosque that he said was guarded by thousands of Muslim men.

"I don't know if our house was burned or not, but when we were running away we heard them asking people to pour kerosene and burn everything down," Khan said.

Eighteen people have died since Monday, some of with bullet wounds, according to Sunil Kumar, medical director of the Guru Teg Bahadur Hospital.

In addition to the deaths, at least 186 people — 56 police officers and 130 protesters — have been injured in the clashes, said Anil Kumar, a New Delhi police spokesman.

Trump told reporters Tuesday that he had heard about the violence but had not discussed it with Indian Prime Minister Narendra Modi. Instead, Trump gloated about a mega-rally Modi and his Hindu nationalist Bharatiya Janata Party-led government organized for him in Modi's home state of Gujarat that drew an estimated 125,000 people.

India has been rocked by violence since Parliament approved the citizenship law in December. Opponents have said the country is moving toward a religious citizenship test, but Trump, in keeping with his tendency not to criticize the leaders of countries he has visited, declined to comment on it.

"I don't want to discuss that. I want to leave that to India and hopefully they're going to make the right decision for the people," he said.

Black smoke rose into the sky over northeastern New Delhi on Tuesday after Hindu protesters set fruit and vegetable shops and a Muslim shrine on fire, witnesses said.

Authorities shut schools in the violence-hit areas.

The Press Trust of India news agency said police arrested one person and detained 20 for questioning for alleged involvement in the violence.

Television images showed streets littered with mangled remains of vehicles, rocks and burned tires in the worst-hit areas of Chand Bagh, Bhajanpura, Gokulpuri, Maujpur, Kardampuri and Jaffrabad, which witnesses pitched battles between the rival groups who also hurled gasoline bombs and opened fire on Monday and Tuesday.

The group of protesting Hindus shouted praise for Hindu gods and goddesses. Police fired tear gas to disperse them and a group of rival Muslims. The two groups retreated to the opposite sides of a highway.

Also Tuesday, protesters in several other areas of northeastern New Delhi defied orders prohibiting the assembly of more than five people, throwing stones and setting several shops and vehicles on fire, said a police officer who spoke on condition of anonymity because he was not authorized to disclose details. Some homes were attacked with rocks.

Police characterized the situation as tense but under control. Police and paramilitary forces sent reinforcements to quell the clashes.

During Monday's protests, police fired tear gas and used canes as they charged at protesters in several areas of New Delhi. The rival groups hurled rocks at each other and set houses, shops, vehicles and a gasoline pump on fire. Police closed two metro stations.

One police officer was killed in the violence after he was hit by rocks, police officer Anuj Kumar said. Eleven other officers were injured by rocks as they tried to separate rival groups, police said.