Iran’s deputy foreign minister, Abbas Araqchi, said the UK ambassador was temporarily arrested for participating in an “illegal gathering” in Tehran, Tasnim reported.

“He wasn't detained but arrested as an unknown foreigner in an illegal gathering. When police informed me a man's arrested who claims to be UK Amb, I said IMPOSSIBLE! only after my phone conversation w him I identified, out of big surprise, that it's him. 15 min later he was free,” Araqchi tweeted on Sunday.

Thus, the deputy FM responded to the reaction of the head of the EU diplomacy,  Josep Borrell, who expressed concern about the temporary detention of the UK ambassador.