Anastasia Shevchenko from the southern city of Rostov-on-Don last month became the first person to be charged under a new Russian law that carries a prison term for "participation in the activities of an undesirable organization."

Shevchenko works for Open Russia, an organization funded by exiled billionaire Mikhail Khodorkovsky. Russia passed a much-criticized law in 2015 to list groups that it believes to be harming national interests as "undesirable."

The TV channel Dozhd reported Sunday about 100 people were rallying in support of Shevchenko in Moscow. Several dozen were also on the streets of St. Petersburg and Yekaterinburg.

Shevchenko is under house arrest, awaiting trial.