Protesters fought with police in New Delhi, India, on Monday over a law facilitating citizenship for people facing religious persecution in Muslim countries.

A policeman and two civilians identified as Muslims were killed just hours before the arrival of visiting U.S. President Donald Trump. Dozens of injuries and about 30 fatalities have been reported in demonstrations against the law since it was passed in December.

The law essentially makes it easier for refugees fleeing religious persecution to apply for Indian citizenship – but not if they are Muslims, who were excluded on the grounds that India is surrounded by Muslim countries, so Muslim refugees needed no special considerations. Detractors of the law describe it as an act of Hindu nationalism and the first step in a plan to deport many of India’s 200 million Muslims.

According to the Times of India, “several paramilitary and Delhi Police personnel” were injured during the second consecutive day of street battles in New Delhi, along with the three persons killed. The death of the police officer marked the first time a member of India’s security forces has been killed during the demonstrations.

“At least three vehicles were set on fire and smoke was seen rising from a house above a closed shop,” Times of India reported.

The weekend saw violent confrontations between supporters and opponents of the citizenship law. One leader of Modi’s BJP Party said his supporters would allow three days for President Trump to complete his visit to New Delhi before demanding the police use all necessary force to clear away roadblocks erected by the protesters. Protest leaders complained they were pelted with stones and assaulted by mobs after this ultimatum was made.

“It’s disturbing that violence has escalated into a full-fledged riot with police forces unable to control mob fury. The death of a police constable manifests the gravity of the madness on the streets of Delhi. Provocative inflammatory speeches from leaders of the ruling dispensation are responsible for encouraging thugs, with police often a mere bystander,” an opposition spokesman charged.

“The culprits must be identified, strictest action should be taken against them. There is after all the death of a police officer and 37 police officials have been injured. This is making a mockery of what is supposed to be a peaceful protest,” a spokesman for Modi’s BJP party countered.

“Parts of the city remain tense as Mr. Trump prepares for talks on Tuesday,” the BBC noted, worrying that the citizenship law has combined with Prime Minister Narendra Modi’s revocation of autonomy for the disputed Kashmir province in August to leave India “sharply polarized.”

AFP on Monday warned of “unease in Washington” over India’s citizenship law, quoting a senior U.S. official who said President Trump intends to discuss religious freedom with Prime Minister Modi during their meetings.

“He will raise these issues, particularly the religious freedom issue, which is extremely important to this administration,” the official said.

A bipartisan group of U.S. senators wrote to Secretary of State Mike Pompeo earlier this month and said the citizenship law, combined with Modi’s actions in Kashmir, “threaten the rights of certain religious minorities and the secular character of the state.” The senators also expressed concerns about excessive force used against those protesting the law.

Modi’s administration has generally rejected foreign criticism of its policies, including a report by the U.S. State Department that warned about religious intolerance in India months before the citizenship law was passed.