Russian news reports have previously indicated that Alexey Navalny, who has been held in a maximum-security jail in Moscow, would likely be sent to a facility in western Russia.
Kremlin critic Alexey Navalny has been transferred from a Moscow jail to an unknown location, his aides said on Thursday, suggesting he may be beginning a prison sentence condemned as politically motivated.
President Vladimir Putin's most prominent opponent was sentenced to more than two years in a penal colony this month for breaching his parole terms while recovering in Germany from a poisoning attack.
Navalny lawyer Olga Mikhailova said the defence team did not know where Navalny was being taken but suggested he could be transferred to a penal colony.
"They didn't tell anyone where he is being sent," Mikhailova told AFP.
Navalny's right-hand man Leonid Volkov said the opposition politician's family has not been informed of his whereabouts, expressing concern over lack of transparency.
Navalny spent months recovering in Germany from the attack with nerve agent Novichok that saw him fall ill on a flight in Siberia in August. Russia has denied involvement.
His arrest upon return to Moscow in mid-January sparked massive protests across the country.
More than 10,000 people were detained, with many of Navalny's allies now under house arrest.
His team has said they will stage fresh demonstrations later this year.
Last week Navalny was also convicted of defamation for calling a World War II veteran a "traitor" for appearing in a pro-Kremlin video and ordered to pay a fine of $11,500.
Supporters of the opposition politician say the criminal cases against him are a pretext to silence his corruption exposes and quash his political ambitions.