Backlash grew around the world Sunday after Russian President Vladimir Putin claimed a huge victory in his country's presidential election.

Putin was re-elected with more than 75 percent of the vote, exit polling data showed, which keeps him as Russia's leader for another six years — marking him as the country's longest-serving ruler other than Joseph Stalin.

The election sparked swift criticism from those who questioned the integrity of the election.

Edward Snowden, the former CIA contractor who gained infamy for leaking hundreds of thousands of classified documents from the National Security Agency in 2013, posted security camera footage of what looked like ballot stuffing. Snowden claimed it was part of "an effort to steal the influence of 140+ million people."

"Demand justice; demand laws and courts that matter," Snowden wrote. "Take your future back."

Garry Kasparov, the former world chess champion and Human Rights Foundation chairman, said Sunday on ABC News' "This Week" to "stop calling it elections. It's a charade. The only vote that matters in a dictatorship like Russia is Putin's vote."

Kasparov followed-up on Twitter, writing that "Every free world leader who congratulates Putin on his 'election' is complicit in his global war on democracy. They undermine their own status as freely elected leaders."

House Intelligence Committee Ranking Member Adam Schiff, D-Calif., also criticized Putin's victory, calling it "easy to get 73 [percent] of the vote when you bar your 'opponents' from running."

Sen. John McCain, R-Ariz., shared similar sentiments.

"That #Putin had to work so hard to drive voter turnout shows the Russian people know his claim to power is a sham," McCain tweeted. "The US stands with all Russians yearning for freedom. #RussiaElections2018."