Britain has condemned the arrest of the UK ambassador to Iran as a “flagrant violation of international law”.

Rob Macaire was detained for a short time on Saturday night after attending a vigil for those who died when Iran’s military shot down a passenger plane.

He left the vigil when it turned into a protest but was later accused of helping to organise the demonstrations.

Iran said he was “an unknown foreigner in an illegal gathering” and summoned him to the foreign ministry on Sunday.

In a statement, Iran’s foreign ministry said Mr Macaire was “reminded” that his presence at “illegal gatherings contravened” the Vienna Convention on diplomatic relations.

BBC diplomatic correspondent James Landale said Mr Macaire was understood to have protested strongly that his detention was unjustified.

Our correspondent says Mr Macaire made clear any suggestion that he was involved in demonstrations was completely untrue, and he was attending an event advertised as a vigil for the victims of Wednesday’s crash – which killed 176 people, including four Britons.

Earlier, Iran’s deputy foreign minister Seyed Abbas Araghchi, who denied Mr Macaire was detained, said in a tweet that he thought it “impossible” when police first told him that the UK ambassador had been arrested.

A phone conversation confirmed Mr Macaire’s identity and he was released 15 minutes later, Mr Araghchi added.

Mr Macaire has denied taking part in protests and Foreign Secretary Dominic Raab condemned his arrest.

He was arrested and held for three hours when he stopped at a barber shop for a haircut on his way back to the UK embassy.

In a tweet the ambassador said he was attending the vigil because it was “normal to want to pay respects”, adding that some of the victims were British.

The ambassador added: “Arresting diplomats is of course illegal, in all countries.”

Prime Minister Boris Johnson and German Chancellor Angela Merkel condemned Mr Macaire’s arrest in a joint statement following a phone call on Sunday, in which they discussed their “shared interests in ensuring Iran never acquires a nuclear weapon”.

And Security Minister Brandon Lewis said on Sunday that the UK ambassador’s arrest was “totally unacceptable” and a breach of the 1961 Vienna Convention.

“Iran does need to step back from that kind of activity and play a proper part in working with partners to de-escalate,” Mr Lewis told Sky’s Sophy Ridge.

Under the convention, diplomats cannot be detained. The Foreign Office is to demand a full explanation.

In a statement issued on Saturday night Mr Raab added: “The arrest of our ambassador in Tehran without grounds or explanation is a flagrant violation of international law.

“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 deescalate tensions and engage in a diplomatic path forwards.”

The Iranian Etemad newspaper shared a picture of the ambassador on Twitter after the Tasnim news agency reported his arrest.

Source: BBC News