Politicians and law enforcement officials in Northern Ireland appealed for calm on Wednesday after a night of anti-immigrant rioting forced people from their homes.

The unrest, which mainly affected the city of Belfast, followed a knife attack on Monday evening in which a 30-year-old Sudanese man who had entered the country illegally and claimed asylum appeared to have tried to cut someone's head off. The suspect has since been charged with attempted murder and other offenses, and police have said they do not think the incident was terror-related.

On Tuesday, peaceful protests against knife crime were hijacked by people carrying clubs and blazing torches who entered streets where immigrants were known to live, apparently intent on revenge.

Deputy First Minister of Northern Ireland Emma Little-Pengelly told Good Morning Ulster she condemned "any and all violence or thuggery that we witnessed on the streets in places across Northern Ireland last night".

She said Northern Ireland, which is part of the United Kingdom, had been appalled by the stabbing incident and that "this violence, this thuggery, this intimidation, it is absolutely unacceptable".

The BBC reported mobs had set fire to houses, cars, and a bus during Tuesday night's unrest and quoted a pastor from North Belfast as saying the property of black people had been targeted. Unrest also broke out in other communities, with a police car torched in Portadown and a Turkish barbershop damaged in Ballyclare.

Claire Hanna, leader of the opposition Social Democratic and Labour Party, told Reuters the violence looked to have been a "race-based pogrom", with hundreds of masked men carrying bottles and bricks starting fires and chanting "foreigners out".

Northern Ireland's fire service said it responded to 62 incidents on Tuesday night in the Belfast area, prompting Michelle O'Neill, Northern Ireland's first minister, to say mobs had been "burning families out of their homes".

Jon Boutcher, chief constable of the Police Service of Northern Ireland, said the violence was a "huge act of self-harm by mindless idiots who are actually only damaging their own futures".

"Last night's policing operation was about protecting life and trying to protect properties," he added, saying officers will locate and charge those responsible.

Naomi Long, Northern Ireland's minister of justice and leader of the Alliance Party, told Radio 4's Today program that "bad faith actors" had incited the riots through online posts.

"What distresses and disturbs me is there are those that prior to yesterday would have struggled to find Belfast on a map who are online, who are sharing incitement and encouragement for people and weaponizing the fear that people genuinely have about what happened to try to turn this into some kind of anti-immigration issue or a racist protest," she said.