KIRILL KUDRYAVTSEV/AFP via Getty Images

Russian police have reportedly detained more than 1,000 people across the country who took to the streets in support of opposition leader Alexey Navalny, a top rival of Russian President Vladimir Putin who was detained last week when he returned to Moscow from Berlin, where he had spent months recovering from a poisoning allegedly carried out by Russia's FSB spy agency. He was handed a 30-day jail term.

Among those reportedly detained at Saturday's rallies was Navalny's wife, Yulia Navalnaya, who had previously said she's been under surveillance since her husband's arrest. She posted a picture of herself inside a police van to her Instagram account, while CNN reports a video on social media shows her being stopped by officers at the entrance to a metro station in Moscow and led to the van. Lyubov Sobol, a prominent activist and lawyer for Navalny's Anti-Corruption Foundation, was also reportedly detained, per Deutsche Welle.

The demonstrations began in the eastern Russian city of Vladivostok and spread west throughout the day, with protesters in some cities bracing frigid temperatures.

Reuters estimates 40,000 people gathered in central Moscow, where mass arrests reportedly began before the protest officially started, DW reports.

Still, the demonstrators remained on the street for what appears to be one of the largest anti-Putin rallies in years. Read more at Deutsche Welle and CNN.