Levada Center, the country's only independent national pollster, must register as a foreign agent or face stiff fines after prosecutors determined that it was the recipient of foreign funding, a news report said Tuesday.
Levada Center received 3.9 million rubles ($126,000) from abroad between late December and March, in particular from George Soros' U.S.-based Open Society Institute, as well as from Italy, Germany, Poland and South Korea, the pro-government newspaper Izvestia reported, citing an unidentified source in the Prosecutor General's Office.
Levada had no immediate comment about the report.
Prosecutors have carried out dozens of checks on nongovernmental organizations in recent weeks to see whether they have abided with a law enacted in November that requires groups that receive foreign funding and engage in political activities to register as "foreign agents." May prominent NGOs have refused to register, calling the government drive an effort to smear their reputations in the public's eyes.
The NGO law is widely seen as part of an attempt by the Kremlin to crackdown on the political opposition after they initiated large protests following disputed State Duma elections in 2011.
It was not immediately clear how prosecutors might have concluded that Levada, whose surveys have tracked a steady rise in disillusionment with President Vladimir Putin's government, was engaged in political activities.
Among the recent Levada surveys that might have irked the government was one that indicated a third of Russians support the release of suspected rioters at the anti-government rally on Bolotnaya Ploshchad last May and of former oil tycoon Mikhail Khodorkovsky.
Levada also found that more than half of Russians agree that the ruling United Russia party is a "party of crooks and thieves" and believe that Prime Minister Dmitry Medvedev's Cabinet is "ineffective."