Iranian opponents of Tehran's regime gathered outside Belfast City Hall on Sunday after US and Israeli strikes killed Supreme Leader Ayatollah Khamenei. They carried flags from Israel, the US and Iranian opposition groups along with images of exiled former Crown Prince Reza Pahlavi and compatriots killed by Iranian authorities. Event organiser Edeh Zamani thanked US President Donald Trump and Israeli Prime Minister Benjamin Netanyahu. Traditional Unionist Voice councillor Ron McDowell and Democratic Unionist Party councillor Dean McCullough attended the gathering. McDowell stated he had supported the group for weeks and described the event as a celebration of hope. Queen's University Belfast academic Gleb Gribakin and his wife Anna attended with placards supporting Ukraine.

A speaker at the gathering called on the UK government to designate Iran's Islamic Revolutionary Guard Corps as a terrorist organisation. A similar gathering occurred outside Belfast City Hall on 14 February with non-subscribing Presbyterian minister Rev Chris Hudson expressing support for regime change in Iran.

Deputy First Minister Emma Little-Pengelly received a high-level security briefing and stated thousands of Northern Ireland residents in Middle East countries face risks from Iran. She urged people from Northern Ireland in the region to register with officials. Little-Pengelly highlighted Iran's funding of terrorism including in the UK and noted the regime's killing of protesters and commission of abuses. Responding to Sinn Fein questions at Stormont, she expressed no regret over pressure on the regime.

The Northern Ireland Assembly debated the strikes on Monday. Traditional Unionist Voice MLA Timothy Gaston from North Antrim referenced nearly 50 years of dictatorship in Iran and persecution of Christians. Democratic Unionist Party MLAs David Brooks and Paul Frew supported actions to prevent Iran acquiring nuclear weapons and called for UK involvement. Paul Frew noted past funding from Iran to groups seeking to harm Northern Ireland. Ulster Unionist Party MLA Doug Beattie backed efforts to block Iran's nuclear development. Sinn Fein First Minister Michelle O'Neill stated the strikes violated the UN Charter. Alliance deputy leader Eoin Tennyson acknowledged Iran's human rights record but described the action as unlawful with risks of escalation and said Iranians should determine their future. People Before Profit MLA Gerry Carroll called the strikes an act of aggression. SDLP leader Matthew O'Toole questioned if such attacks promote peace in the Middle East.

Anti-war events occurred on Monday evening. Derry Anti-War Coalition planned a vigil at 6pm at the War Memorial in Derry's Diamond. A Stop Bombing Iran rally took place at 6pm outside Belfast City Hall with People Before Profit MLA Gerry Carroll among the speakers.