Washington: Update: Iran's deputy foreign minister said on Sunday that Britain's ambassador to Tehran, Rob Macaire, was arrested as a foreigner at "an illegal gathering" but was freed soon after being identified.
"He wasn't detained, but arrested as unknown foreigner in an illegal gathering," Seyed Abbas Araghchi tweeted, adding Macaire was released 15 minutes after he called the British diplomat to confirm his identity.
Meanwhile, Iranian protesters set alight a Union Jack in front of the UK embassy in Tehran Sunday, after the British ambassador's arrest for allegedly attending an illegal demonstration, AFP correspondents reported.
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.
'I wasn't taking part in any demonstrations'
Britain's ambassador to Tehran denied Sunday that he took part in a demonstration that broke out at a memorial for the 176 people killed when a plane was shot down.
Students held a gathering at Tehran's Amir Kabir University on Saturday evening to honour those killed hours after Iran admitted the Ukrainian airliner was downed by mistake.
Iran's Mehr news agency said the ambassador, Rob Macaire, was arrested for his alleged "involvement in provoking suspicious acts" at the gathering in front of the university.
"Can confirm I wasn't taking part in any demonstrations! Went to an event advertised as a vigil for victims of #PS752 tragedy," Macaire said on Twitter, adding he had been detained half an hour after leaving the area.
"Normal to want to pay respects - some of victims were British. I left after 5 mins, when some started chanting," he said.
"Arresting diplomats is of course illegal, in all countries," he added.
The British government said Macaire was arrested and detained briefly in the Iranian capital in what it called a "flagrant violation of international law".
Iran arrests UK ambassador, US demands an apology
The United States called Saturday on Iran to apologise for detaining the British ambassador to Tehran, reportedly during protests against the regime.
“This violates the Vienna Convention, which the regime has a notorious history of violating. We call on the regime to formally apologize to the UK for violating his rights and to respect the rights of all diplomats,” State Department spokeswoman Morgan Ortagus tweeted.
A British envoy to Tehran was arrested for several hours in front of Amir Kabir University for “inciting” anti-government protesters, the Tehran-based Tasnim news agency said on Saturday.
Iran has witnessed anti-government protests, as protesters in Tehran on Saturday chanted slogans against the nation’s top authorities, after the powerful Revolutionary Guards admitted shooting down a passenger plane, killing all 176 aboard.