Northern Ireland: Police urge calm after 'sickening' Belfast stabbing

Police in Northern Ireland said they had arrested a Sudanese national over a knife attack that left one person with serious wounds and is currently being treated as attempted murder but not a suspected act of terrorism.

They also called for calm from the public amid calls from far-right figures for anti-migration protests, a year after a week of rioting shook Northern Ireland following the alleged attempted rape of a schoolgirl.

Northern Ireland's Assistant Chief Constable Ryan Henderson declared Monday night's crime a "critical incident" but said investigators had found no indications of a terrorist motive as yet.

"I understand that last night's attempted murder will ‌leave people ​feeling a range of emotions, from fear to anger," Henderson told a press conference . "I appeal for calm and the safety of all of our communities in response to ​this."

The victim, a man in his 40s, suffered severe injuries to his eyes and slash wounds to his face and back in the attack involving a kitchen knife, Henderson said.

Footage of the crime circulating online showed a number of members of the public stepping in before police arrived on the scene as the suspect, a 30-year-old Sudanese man, continued attacking the victim after he had fallen to the ground.

The suspect was arrested on suspicion of attempted murder, Henderson said. He said that based on preliminary information the man lived locally, having been granted leave to remain in the area after moving there from Dublin south of the inner-Irish border.

"He is in custody and at this time we not seeking anyone else in connection with this investigation," Henderson said.