More than 5,100 protesters were detained by authorities in Moscow and across Russia during mass rallies on Sunday in support of Kremlin critic Alexei Navalny.
The Associated Press reported that hundreds of protesters chanted “Putin, resign!” and “Putin, thief!” as they marched through Moscow’s city center, referring to Russian President Vladimir Putin.
One of the largest rallies was held in eastern Siberia, according to the AP, where about 90 protesters were detained in the city of Novosibirsk.
More than 100 demonstrators were also detained in Vladivostok, according to the news service.
Reuters reported that Navalny’s allies said on social media that his wife, Yulia Navalnaya, was detained at a protest in Moscow, noting that she was detained at a similar demonstration last week.
Russian police detained more than 3,000 protesters who rallied last Sunday despite frigid temperatures and warnings that they would be subject to arrest.
The latest demonstrations come after Secretary of State Antony Blinken said that the U.S. had a “deep concern” about Russia’s treatment of Navalny.
“We have a deep concern for Mr. Navalny’s safety and security and the larger point is that his voice is the voice of many, many, many Russians and it should be heard, not muzzled,” Blinken told reporters at a press briefing last Wednesday.
Asked if the U.S. would rule anything out if Navalny is harmed or the demonstrators were to be jailed after protesting his imprisonment, Blinken replied that administration officials are “not ruling out anything” but “want to get this full review done and then we’ll take it from there.”
One day earlier, President Biden discussed Navalny and other concerns during his first call with Putin since becoming president.
The State Department and White House have demanded Navalny’s immediate release and rebuked Russia’s crackdown on sweeping protests.
Navalny returned to Moscow earlier this month and was detained at the airport.
Last year, he fell ill on a flight to Siberia and was taken to a hospital in Berlin, where doctors determined he had been poisoned by the Soviet-era nerve agent Novichok.
Soon after leaving the hospital, the Kremlin told him that unless he returned to Moscow immediately, he would be in violation of the terms of a 2014 suspended sentence and be subject to arrest.
Updated at 5:40 p.m.