Iranians burn UK flag outside embassy following envoy's arrest
Chanting "Death to Britain", up to 200 protesters rallied outside the mission a day after the brief arrest of British ambassador Rob Macaire at a memorial for those killed when a Ukraine airliner was shot down.
The British ambassador was detained for around an hour on suspicion of "organising suspicious movements" outside the Amirkabir University of Technology, Tasnim said on its official Farsi-language Twitter account.
On Sunday, Macaire denied the allegations, saying he attended the tribute to those killed in the Ukrainian passenger jet - including two Britons - and left after the vigil turned into a protest.
British Foreign Secretary slammed his arrest as a "flagrant violation of international law". As a diplomat, Macaire should be immune from arrest and prosecution.
"The arrest of our ambassador in Tehran without grounds or explanation is a flagrant violation of international law," Raab said in a statement.
"The Iranian government is at a cross-roads moment. It can continue its march towards pariah status with all the political and economic isolation that entails, or take steps to de-escalate tensions and engage in a diplomatic path forward."
Tasnim said the ambassador, who was appointed to the post in 2018, was arrested on suspicion of "organising suspicious movements" outside Tehran's Amirkabir University of Technology.
Videos shared on social media showed hundreds of protesters gathered outside the university on Saturday.
"Commander-in-chief resign, resign," the demonstrators chanted, referring to the Islamic Republic's Ayatollah Ali Khamenei.
In other videos, demonstrators were captured chanting "death to liars" and "death to the dictator".
Anti-government protests late last year saw a bloody crackdown that killed an estimated 1,500 people.
Nevertheless, demonstrators returned to the streets on Saturday after Iran admitted to accidentally downing the Ukraine International Airlines jet with a surface-to-air missile.
All 176 people on board the flight were killed in the catastrophic crash, which occurred just hours after Tehran fired a volley of ballistic missiles at two bases in Iraq hosting US forces. That attack came in retaliation for the killing of top Guards general Qasem Soleimani in a US drone strike last week.
Most of the victims were Iranian citizens or Iranian-Canadian dual nationals.