LONDON — Police said early Monday that there were “a number of casualties” and that one person was arrested after a van struck a crowd of pedestrians in London.

The incident occurred just after midnight in the northern part of the city, near the Finsbury Park Mosque. Police said they were dealing with “a major incident.”

Early witness reports suggested that pedestrians had been struck as they left late-night prayers for the holy month of Ramadan.

The Muslim Council of Britain tweeted: “We have been informed that a van has run over worshippers as they left #FinsburyPark Mosque. Our prayers are with the victims.”

Video posted on social media showed people screaming as bystanders performed chest compressions on one of the injured, and another man held a bloody cloth to his head.

The Finsbury Park Mosque, located in a multicultural area of north London, was once closely associated with extremism. But in the past decade, the mosque has transformed its image, with its leadership outspoken in advocating interfaith harmony.

During the 2016 U.S. presidential campaign — amid the furor of candidate President Donald Trump’s proposed Muslim ban — U.K. Labour Party leader Jeremy Corbyn invited Trump to visit Finsbury Park Mosque to show him how “multicultural, multifaith” Britain works.

The incident Monday follows two recent terrorist attacks in London in which vehicles have been used as weapons. Eight people were killed this month when attackers used a van to plow into pedestrians on London Bridge, then got out to stab restaurant-goers with knives. In March, a lone attacker drove his car into people on Westminster Bridge, then fatally stabbed a police officer.