Updated

Russian opposition leader Alexei Navalny is expected to make a court appearance after being detained at a major opposition rally the previous day.

Tens of thousands of protesters took to the streets across Russia on Sunday in the biggest show of defiance since the 2011-2012 anti-government protests.

Almost all of Sunday's rallies were unsanctioned. A group that monitors political repression, OVD-Info, published a list early Monday of more than 1,000 people arrested at the Moscow rally. This number can't be immediately verified, and the Moscow police previously reported half as many arrests.

Sunday's protests were led by Navalny, a charismatic opposition leader who has recently announced his bid for presidency. Navalny was detained while walking to the rally from a nearby subway station.