Yulia Navalnaya, the wife of the Kremlin critic Alexey Navalny, was arrested in Moscow on Saturday amidst the protest held in support of her husband.

Navalnaya was stopped by police at the entrance to a metro station in central Moscow near where protesters were gathered. She was then escorted to a police van and was released later on Saturday, according to a tweet from Navalny's Anti-Corruption Foundation.

The demonstration in Moscow was one of the dozens of opposition rallies held in defiance of the authorities across Russia on Saturday. According to OVD-Info, an independent site that monitors arrests, more than 2,100 people were detained during various protests in nearly 100 cities.

Navalny himself is currently being held in pre-trial custody and the protesters are demanding his release. He was detained at a Moscow airport late Sunday,  moments after arriving from Germany, where he spent five months recovering from Novichok poisoning he blamed on the Russian government. The Kremlin repeatedly denied any involvement.
The demonstrations kicked off in Russia's far eastern city of Vladivostok and spread to the west as the days progressed. Navalny's supporters are reportedly planning protests across 90 cities.

 Thousands of people gathered at Pushkin Square in central Moscow in the early afternoon, carrying banners and chanting "Putin is a thief" and "One for all and all for one!" Armed police were trying to control the situation by using batons and asked them to leave. The Russian Ministry of Internal Affairs said the protesters in Moscow numbered around 4,000. 

Numbers of protesters were arrested even before the riots officially started. By the end of the day, more than 500 had been detained in Moscow alone, according to OVD-Info.