FILE PHOTO: Russian opposition politician Alexei Navalny takes part in a rally to mark the 5th anniversary of opposition politician Boris Nemtsov's murder and to protest against proposed amendments to the country's constitution, in Moscow, Russia February 29, 2020. REUTERS/Shamil Zhumatov

MOSCOW (Reuters) - A Russian court on Thursday fined opposition politician Alexei Navalny’s Anti-Corruption Foundation 500,000 roubles ($7,536) for failing to identify itself as a foreign agent on social media, Navalny’s spokeswoman said.

Russia’s Justice Ministry formally labeled the group a foreign agent in October after Navalny called on people to attend rallies that grew into Moscow’s biggest sustained protest movement in years before fizzling out.

Civil society groups designated as foreign agents, a term that carries a negative Soviet-era connotation, can be subjected to spot checks and face intense bureaucratic scrutiny.

MBK media, an outlet financed by Kremlin critic and former oil tycoon Mikhail Khodorkovsky, reported that Navalny’s group had been fined by the court for not identifying itself as a foreign agent on Instagram.

Kira Yarmysh, Navalny’s spokeswoman, confirmed the report.

Navalny has tried unsuccessfully to contest the foreign agent designation in court, something he has cast as part of a coordinated government campaign aimed at stifling his activities.

Navalny was barred from running for president in 2018 because of a past conviction on charges he has called trumped up. Putin won that election by a landslide.

On Tuesday, Navalny accused authorities of emptying and blocking his bank accounts and those of his close family, a move he said was unfair and aimed at strangling him and his supporters financially.

He said authorities were seeking to sideline him at a sensitive political time when Putin is pushing for major constitutional changes and may be thinking of calling snap parliamentary elections this autumn.