NATO Secretary General Jens Stoltenberg has tweeted that Russian opposition leader Alexei Navalny must be released immediately.
"I join international calls for the immediate release of Alexei Navalny. Those responsible for the attempt to assassinate him, using a prohibited chemical weapon, must be brought to justice. Russia has to respect its international commitments on human rights and the rule of law," Jens Stoltenberg tweeted.
Russian opposition activist Alexei Navalny has been sentenced to 30 days in jail a day after returning to the country, following threats from EU member states to impose new sanctions against Moscow if he was not released.
Mr Navalny was detained by police at Moscow’s main airport on Sunday evening after returning from Germany where he had recovered from an assassination attempt involving use of a nerve agent from the novichok group.
The attempt on his life in August last year was blamed on the Kremlin and sparked widespread condemnation from western governments. Moscow denied any involvement and has suggested Mr Navalny could have been poisoned outside Russia.
The anti-corruption campaigner, who has emerged as president Vladimir Putin’s most vocal critic, was found guilty of breaching the terms of a suspended sentence on Monday by a hastily assembled makeshift court set up in the police station where he was held overnight, according to his lawyer.