LONDON — Thousands of demonstrators gathered in Belfast on Saturday to denounce anti-immigrant rioters who set fire to homes and cars earlier in the week after a brutal stabbing blamed on an asylum seeker.

The anti-racism rally came after nights of fiery violence in parts of Northern Ireland following the arrest of a 30-year-old man from Sudan on charges of attempted murder in a stabbing that left a man partly blind.

Protests turned violent when groups of masked men set fire to several homes they believed to house immigrants, torched a bus and pelted police with bricks, bottles and firebombs. More than two dozen people were left homeless and 12 police officers were injured in what officials called “thuggery.”

“All it takes is for one person who’s not white and local to commit a crime and that fire of racism is rekindled,” Elaine Crory told the crowd gathered outside Belfast City Hall.

Peaceful demonstrators carried signs saying, “The problem is evil & violence not race,” “Your racism is not patriotism” and “Protect people not prejudice.”

Newlyweds Cara Bell and Matthew Richardson said it was a happy coincidence to emerge from getting married in City Hall and joining the peaceful demonstration after the ugly violence they witnessed earlier in the week.

“It’s important to note that things like today really show that this is not the general feeling of people in Belfast,” Bell said, noting it was “a week where you’ve seen the worst of humanity and the best of humanity in Belfast.”

Despite calls for calm by officials and the family of the victim, far-right and anti-immigrant figures were blamed for whipping up protests in several place across the U.K. earlier in the week.

Disorder in Glasgow, Scotland, targeted minorities and terrified worshippers at a mosque went into lockdown, police said.

On Saturday, an anti-racism group rallied thousands to reclaim Glasgow streets and “stand up to the far right.”

The group was met by a much smaller contingent of mostly men who appeared to make Nazi salutes and shouted anti-Muslim chants.

The anti-racism group shouted, “Nazi scum off our streets.”