MOSCOW (AP) — The Latest on Russian opposition protests (all times local):

10:25 a.m.

The European Union is calling on Russian authorities to release demonstrators detained during a series of protests across the country on Sunday.

Russia's opposition staged dozens of protests on Sunday and hundreds were arrested — including Alexei Navalny, the anti-corruption campaigner who is President Vladimir Putin's most prominent critic.

The EU's foreign policy arm said in a statement early Monday that police operations "prevented the exercise of basic freedoms of expression, association and peaceful assembly — which are fundamental rights enshrined in the Russian constitution."

It called on Russia to abide fully by its international commitments to uphold those rights "and to release without delay the peaceful demonstrators that have been detained."

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10:15 a.m.

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.