Leading Russian dissident Alexei Navalny has apparently been detained in an infamous detention centre in Moscow just days after his return to the country from Germany.
Navalny was taken to the Matrosskaya Tishina (Sailor's Silence) detention centre on Monday evening, a spokesman for the Public Monitoring Commission rights group in Moscow wrote in his Telegram channel.
The prison is known for a series of unexplained deaths, including that of the lawyer Sergei Magnitsky in 2009.
Russian authorities have not commented on the whereabouts of the 44-year-old opposition member, who was arrested at Moscow's Sheremetyevo airport on Sunday evening immediately after his arrival.
According to the commission spokesperson, Navalny is doing relatively well in detention. He is "happy to be back home" and the prison guards have so far exerted "no moral or physical pressure" on him.
Navalny, who returned from Germany where he had been recovering from an assassination attempt with the nerve agent Novichok, was sentenced to 30 days of pre-trial detention at a controversial snap trial on Monday.
He is alleged to have violated probation requirements in a previous criminal case. Navalny and his team criticized the process as a politically motivated attempt to silence him.