United Russia is set to lose many seats, but will retain a majority in the city parliament.Read more
Moscow city elections 2019
Dmitry and Olga Prokazov also face a criminal case after footage featuring their baby was posted online.
Thousands of Russians have been protesting for weeks - with mass arrests and a violent police crackdown.
Dozens of opposition supporters were arrested after taking part in an unauthorised "stroll".
Police dragged Russian opposition activist Lyubov Sobol out of an official building on a sofa.