An activist holds a placard outside a terminal before the expected arrival of Russian opposition leader Alexei Navalny on a flight from the German capital Berlin at Vnukovo International Airport in Moscow, Russia January 17, 2021. A placard reads: "Love is stronger than fear".

A view shows a police station where detained Russian opposition leader Alexei Navalny is being held, in Khimki outside Moscow, Russia January 18, 2021.

Yulia Navalnaya, wife of Russian opposition leader Alexei Navalny, walks past journalists and supporters after police detained her husband on arrival at Sheremetyevo airport in Moscow, Russia January 17, 2021.

A man holds a placard reading "For Navalny!" as people, including supporters of Alexei Navalny, gather outside a police station where the Russian opposition leader is being held following his detention, in Khimki outside Moscow, Russia January 18, 2021.

Law enforcement officers stand guard before the expected arrival of Russian opposition leader Alexei Navalny on a flight from the German capital Berlin at Vnukovo International Airport in Moscow, Russia January 17, 2021. Handout via REUTERS

Russian opposition leader Alexei Navalny and his wife Yulia Navalnaya are seen on board a plane during a flight from Berlin to Moscow, January 17, 2021.

An ally of Russian opposition leader Alexei Navalny accompanied by police officers enters a police station where detained Navalny is being held, in Khimki outside Moscow, Russia January 18, 2021.

A still image taken from video footage shows law enforcement officers speaking with Russian opposition leader Alexei Navalny before leading him away at Sheremetyevo airport in Moscow, Russia January 17, 2021.

Russian opposition leader Alexei Navalny and his wife Yulia Navalnaya are seen on board a plane after landing at Sheremetyevo airport in Moscow, Russia January 17, 2021.

Russian opposition leader Alexei Navalny and his wife Yulia Navalnaya wait before leaving a plane after landing at Sheremetyevo airport in Moscow, Russia January 17, 2021.

Olga Mikhailova and Vadim Kobzev, lawyers of Russian opposition leader Alexei Navalny, talk to a police officer outside a police station where detained Navalny is being held, in Khimki outside Moscow, Russia January 18, 2021.