In simultaneous morning raids in 43 cities on Thursday, Russian security services descended on the homes and offices of supporters of Russian opposition leader Alexei Navalny whose "Smart Voting" movement is credited with drastically reducing the number of pro-government members of the Moscow city council.

Police also searched the home of Sergei Boyko, a Navalny associate who came in second with nearly 20% of the vote in the mayoral election in Russia’s third-largest city of Novosibirsk last Sunday.

More than 150 raids were carried out, from Vladivostok on the Pacific to Krasnodar in Russia’s south, according to Navalny's close allies.

Police also targeted Navalny's Anti-Corruption Foundation, which has worked to expose officials' questionable wealth, for what authorities said was an investigation of alleged money laundering.

In some offices, investigators cut off cables and video surveillance cameras, according to the Russian investigative newspaper Novaya Gazeta.

In addition to Navalny's campaign organization, the raids also hit activists of the Golos (Voice) Movement, a respected independent election monitoring group.

The lead up to last weekend's local elections included a series demonstrations — some authorized, some not — protesting the rejection of many independent candidates from the Moscow City council.

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Despite the disqualification of many of the independent candidates, Navalny's Smart Voting movement sought to game the system by calling on supporters to vote for any nongovernment-related candidates, including members of the Communist Party. Putin's party is the United Russia party.

In Moscow, the results of Sunday's voting left the United Russia party with a slim majority on the 45-member council, dropping from 38 to 25.

Navalny, in a broadcast on YouTube, described the raids as part of Kremlin "hysteria" over the big losses in local elections.

"Putin got upset and is stomping his feet," Navalny said.

On his website Thursday, Navalny said he believes the government understands the growing power of his movement. "The Kremlin knows how to count," he said. "We just underestimate our strength, but they all understand."

Navalny was barred by authorities from running against Putin in the 2018 presidential election, but his supporters in local elections across the country have strengthened in dozens of Russian cities and now also investigate high-level corruption and mobilize supporters for opposition rallies.

“We’re obviously talking about an attempt to hamper the operations of our regional network,” Leonid Volkov, chief of staff for Navalny's ill-fated presidential campaign, told The Associated Press.

Contributing: Associated Press