Iran deployed riot police in the capital on Sunday expecting possible protests after its Revolutionary Guard admitted to accidentally shooting down a passenger plane at a time of soaring tensions with the United States.
Riot police and plainclothes officers could be seen massing in Vali-e Asr Square in Tehran as calls circulated for protests later in the day. A large black banner unveiled in the square bore the names of those killed in the plane crash.
The plane crash early Wednesday killed all 176 people on board, mostly Iranians and Iranian-Canadians. After initially blaming a technical failure, authorities finally admitted to accidentally shooting it down in the face of mounting evidence and accusations by Western leaders.
The plane was shot down as Iran braced for retaliation after firing ballistic missiles at two bases in Iraq housing American forces. The ballistic missile attack, which caused no casualties, was a response to the killing of Gen. Qassem Soleimani, Iran's top general, in a US airstrike in Baghdad.
Iranians have expressed anger over the downing of the plane and the misleading explanations from senior officials in the wake of the tragedy. A candlelight ceremony late Saturday in Tehran turned into a protest, with hundreds of people chanting against the country's leaders including Supreme Leader Ayatollah Ali Khamenei and police dispersing them with tear gas.
Police briefly detained the British ambassador to Iran, Rob Macaire, who says he went with the intention of attending the vigil and did not know it would turn into a protest. Later, Iran's deputy foreign minister said Macaire was arrested as a foreigner at "an illegal gathering" but was freed soon after being identified.