A Delhi Police constable was among four people killed on Monday after supporters of the Citizenship Amendment Act clashed with those opposing it in North East Delhi, PTI reported. At least 50 people, including policemen and paramilitary forces, were injured. The violence erupted just ahead of United States President Donald Trump’s first visit to the city for talks with Prime Minister Narendra Modi.

The head constable, identified as 42-year-old Ratan Lal, was attached to the office of the assistant commissioner of police in Gokulpuri. Shahdara Deputy Commissioner of Police Amit Sharma and Gokalpuri Assistant Commissioner of Police Anuj Kumar were among the police personnel who were injured while trying to quell the protests. Two personnel of the Central Reserve Police Force were also injured, PTI reported.

Here’s what we know so far about the violence that erupted in Delhi today

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Prohibitory orders under Section 144 of the Criminal Procedure Code were imposed at 10 locations in Delhi. Incidents of violence and arson were reported in Maujpur, Kardampuri, Chand Bagh and Dayalpur areas. Vehicles, shops, houses and a petrol pump were set on fire. Two mini-trucks were also vandalised, and a fire tender torched.

A Scroll.in reporter saw police personnel fire tear gas shells in Maujpur area to disperse anti-Citizenship Act protestors around 3.45 pm. However, a little ahead, a group supporting the amended law stood undisturbed. The men brandished sticks, one of them carrying a sword. Videos from the site showed them shouting “Jai Shri Ram” and “Bharat Mata Ki Jai”.

Supporters of the Citizenship Amendment Act were seen jumping police barricades, committing arson and attacking a Muslim man. Stones, pieces of bricks and glass shards lay strewn on roads and smoke billowed from houses, shops and vehicles set on fire, PTI reported.

At least three vehicles were set on fire and smoke was seen rising from a house above a closed shop. The police used tear gas to counter demonstrators. However, the mobs kept on returning. While the anti-Citizenship Act protestors shouted “Inquilab Zindabad”, supporters of the law shouted “Jai Shri Ram” and played bhajans praising Ram.

In another video, a man in a red shirt was seen running towards an police officer waving what appeared to be a gun and then fired into the air, NDTV reported.

The Delhi Police appealed to residents to maintain peace and harmony. “It is appealed to the people of Delhi and particularly to the North East district to maintain peace and harmony and not to believe in any rumours,” the police said. “It is also appealed to the media not to circulate any disturbing pictures which may further aggravate the situation.”

Security forces conducted a flag march in Maujpur after the mob had dispersed. Following the violence, the Aam Aadmi Party government in Delhi announced that all government and private schools will be closed in North East district on Tuesday.

Chief Minister Arvind Kejriwal urged Lieutenant Governor Anil Baijal and Union Home Minister Amit Shah to restore law and order in the national Capital. “Very distressing news regarding disturbance of peace and harmony in parts of Delhi coming in,” he tweeted. “I sincerely urge Hon’ble LG and Hon’ble Union Home Minister to restore law and order and ensure that peace and harmony is maintained. Nobody should be allowed to orchestrate flagrations.”

Baijal said he instructed police to ensure that law and order is maintained in Delhi. “The situation is being closely monitored,” he tweeted. “I urge everyone to exercise restraint for maintenance of peace and harmony.”

Deputy Chief Minister Manish Sisodia appealed to the people of Delhi to maintain peace. “Everyone loses from violence,” he tweeted. “The fires of violence can cause losses, which cannot be compensated ever.”

Meanwhile, the Delhi Metro Rail Corporation closed Gokulpuri, Johri Enclave and Shiv Vihar stations. Trains on the Pink Line will now terminate at Welcome metro station. Entry and exit gates of Jaffrabad and Maujpur-Babarpur have been closed since Sunday.

Delhi minister and Babarpur MLA Gopal Rai also urged the people to maintain peace, saying some people were purposely trying to disturb the atmosphere.

Clashes first broke out on Sunday evening, soon after Bharatiya Janata Party leader Kapil Mishra gave the police a three-day ultimatum to stop an anti-CAA protest that began in Jaffrabad on Saturday night, involving around 500 people, mostly women. Mishra said he would not listen even to the police after three days. After both sides shouted slogans, the groups started pelting stones at each other, leading to chaos in the area.