In Russia, thousands of people took part in unauthorised protests to demand the release of the jailed opposition leader Alexei Navalny. A monitoring group said, over 5,000 people have been detained.
In Moscow, police closed metro stations and blocked off the city centre. Mr Navalny was jailed on his return to Russia after recovering from an attempt to kill him with a nerve agent. He blames the security services for the attack but the Kremlin denies this.
The opposition figure was arrested
after arriving in Moscow from Germany, where he spent months recovering from the near-fatal incident.
Russian authorities said, Mr Navalny was supposed to report to police regularly because of a suspended sentence for embezzlement.
Mr Navalny has denounced his detention as blatantly illegal, saying the authorities had allowed him to travel to Berlin for treatment for the Novichok poisoning, which happened in Russia in August last year.