Russian authorities have arrested over 13,000 anti-war protesters as its crackdown on dissidents within the country continues.

People across the country are protesting Russian President Vladimir Putin's decision to invade Ukraine, beginning a war that has killed at least 331, according to the United Nations.

OVD-Info, an independent human rights project focused on political persecution in Russia, published the figure on Sunday.

The arrests come after Putin has increased attempts to stifle any opposition to the government's invasion of Ukraine, also blocking several major social media outlets within the country, such as Facebook and Twitter.

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Russian President Vladimir Putin spoke to female flight attendants in comments broadcast on state television on Saturday, March 5, 2022. (Image: Reuters Video)

Russian President Vladimir Putin spoke to female flight attendants in comments broadcast on state television on Saturday, March 5, 2022. (Reuters Video)

One human rights activist, Marina Litvinovich, called for mass protests last week in a Facebook video, stating that the Russian people oppose the war. 

"We, the Russian people, are against the war Putin has unleashed. We don’t support this war, it is being waged not on our behalf," Litvinovich said. "I know that right now many of you feel desperation, helplessness, shame over Vladimir Putin’s attack on the friendly nation of Ukraine. But I urge you not to despair."

She was arrested shortly after uploading the video to Facebook.

Anti-war activist in Russia, Tatyana Usmanova, asked Ukrainians for forgiveness after Russian President Vladimir Putin's announcement to invade Ukraine on Feb. 24, saying "our confrontation with these [Ukrainian] forces is inevitable."

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Russian Police officers detain a woman during an unsanctioned protest rally against the military invasion on Ukraine, March,6,2022, in Central Moscow, Russia. Police detained about 3500 people at anti-war protests across Russia, including 1750 in Moscow on Sunday, the Interior Ministry officials said. (Photo by Konstantin Zavrazhin/Getty Images)

"I want to ask Ukrainians for forgiveness. We didn’t vote for those who unleashed the war," she said.

Putin also signed a law on Friday which aims to punish journalists with prison time for publishing news that contradicts the government's statements about Russia's war in Ukraine.

People who violate the law will face up to 15 years in prison.

The protests aren't limited to the streets either, with some people signing open letters expressing their opposition to Russia's invasion of Ukraine. 

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 Russian Police officers detain a man during an unsanctioned protest rally against the military invasion in Ukraine on March 6, 2022 in Moscow, Russia. Russia invaded neighboring Ukraine on 24th February 2022, its actions have met with worldwide condemnation with rallies, protests and peace marches taking place in cities across the globe. (Photo by Vladimir Pesnya/Epsilon/Getty Images)

One Museum in Moscow, Garage, said that it would be halting and postponing work on exhibitions "until the human and political tragedy that is unfolding in Ukraine has ceased."

"We cannot support the illusion of normality when such events are taking place," the statement by the museum read. "We see ourselves as part of a wider world that is not divided by war."

The Associated Press and Fox News' Louis Casiano contributed to this report.