Russian police have raided the Moscow offices of Kremlin critic Alexei Navalny's Anti-Corruption Foundation and state bailiffs say a criminal investigation had been opened against the group's director.
Navalny, who is convalescing in Germany after his alleged poisoning with a novichok nerve agent in Russia, posted images on social media of law enforcement officers at his group's offices in a business centre in Moscow.
The RIA news agency cited bailiffs as saying the raid was linked to a criminal case against Ivan Zhdanov, director of Navalny's group, for failing to implement a court order, an apparent reference to a lawsuit payout.
A court in Moscow ordered Navalny's Anti-Corruption Foundation and Navalny supporter Lyubov Sobol last month each to pay 29 million roubles ($A517,230) for libelling the Moscow Schoolchild catering company.
The Kremlin's critics have cast those lawsuits as well as a series of mass police raids as part of a coordinated campaign aimed at crippling their activities, a charge that Russian authorities deny.