President of the European Council, Charles Michel, has stated that the detainment of Russian opposition leader Alexei Navalny is unacceptable.

"The detainment of Alexey Navalny upon arrival in Moscow is unacceptable. I call on Russian authorities to immediately release him," Michel wrote on Twitter.

Alexei Navalny arrived at Sheremetyevo Airport on the evening of January 17 and was detained after passing through passport control. Navalny will be detained before the start of the trial.

The plane, with Alexei Navalny also on board, landed at Sheremetyevo International Airport of Moscow on Sunday evening, and he was detained immediately after passing through passport control. He will be remanded in custody until the start of his trial.