Memorial International, Russia's most venerated human rights group, says police have raided one of its offices in Moscow.
"The office of Memorial on Karetny Ryad [street] is being searched," the group said in a post on its Telegram channel on March 4.
TASS news agency quoted a source close to law enforcement as saying that the searches were linked to the case of well-known human rights activist Bakhrom Khamroev, who was arrested last month on a charge of justifying extremism, which he rejected as politically motivated.
According to OVD-Info, a nonprofit that monitors police arrests nationwide, police also searched the offices of Civic Assistance, an organization that provides legal assistance to refugees and migrants in Russia.
Civic Assistance said that officers of the Federal Security Service (FSB) conducted the search. The reason for the search remains unclear.
Russia's Supreme Court in December ordered the closure of Memorial, claiming it violated the onerous "foreign agent" law, which is increasingly being used by officials to shutter civil-society and media groups.
Memorial has appealed the ruling and said its work has not stopped, since parts of the organization are not legal entities.
After the Russian Supreme Court decision on liquidating Memorial International, the European Court of Human Rights ordered the Russian government to suspend implementation of the decision pending the resolution of a case contesting the "foreign agent" laws brought by a group of Russian NGOs, including Memorial.