Anti-immigration protests break out in Belfast after knife attack

Following a knife attack in Belfast, Northern Ireland's political leaders have urged for calm amidst anti-immigration protests that have erupted in the capital. The article states that the protests were a direct consequence of the knife attack. Political leaders are actively calling for a de-escalation of tensions in response to the events. The specific details of the knife attack, such as the victim or perpetrator, are not provided in the article content. The focus of the article is on the reaction of political leaders to the protests that followed the incident.