Russian opposition activist Alexei Navalny was detained by police on Sunday evening as he landed in Russia, having returned from Germany where he had recovered from an assassination attempt blamed on the Kremlin.

Mr Navalny, President Vladimir Putin’s best known and most outspoken critic, was detained upon arrival in Moscow, after his flight from Berlin was diverted from Vnukovo airport where hundreds of his supporters had gathered and clashed with riot police.

In a joint statement, EU members Estonia, Latvia and Lithuania described his detention as “completely unacceptable” and called for “restrictive measures” if he was not released. “[The] EU should act swiftly and if he is not released, we need to consider imposition of restrictive measures in response to this blatant act,” the countries’ foreign ministers said.