Activist Alexei Navalny is an outspoken critic of the Kremlin and has been exposing the corruption of top officials.
Navalny was rushed to hospital on Sunday after showing symptoms of an allergic reaction, which his team say was caused by a poisoning attempt.
Nastya Rybka claims she was once the mistress of Oleg Deripaska, a Kremlin-linked Russian oligarch whose core businesses are currently under U.S. sanctions.
"We consider all justified appeals from state bodies," Google said in a statement. "We also require advertisers to act in accordance with the local law and our advertising policies."
The election commission's website was hit by DDoS attacks from 15 countries, officials claimed.
"The Kremlin is trying to find safer ways to sex up the [presidential] campaign—and Sobchak is ideal."
Navalny has rallied thousands to protests in Russia but the electoral commission says he has "no chance" of running in 2018.
Chief Vladimir Putin critic Alexei Navalny was arrested Monday for the second time in three months.
Authorities are facing mass opposition to plans to forcibly remove residents from their homes in favor of new construction that many say will only benefit rich developers and their partners in government.
Authorities have blocked web pages calling for demonstrations one week after arresting hundreds in anti-Moscow protests.
Police sweep through opposition leader's anti-corruption foundation hours after making arrests at protests throughout the nation.
Dozens of protesters were detained after thousands took to the streets to demand the resignation of the prime minister.
The "Yarovaya Law" could introduce the most sweeping snooping powers since Soviet times.
Alexey Navalny has announced his Party of Progress will not run alongside the Parnas party.
The music video is based on Putin critic Alexey Navalny's recent investigation.
A coalition led by Alexei Navalny has been refused a place on the ballot.
Putin has kept his two daughters out of the limelight, fueling speculation about who and where they are.
Navalny's party is contesting three regions in the municipal elections.
The opposition leader thanked supporters and vowed to fight on.
Amid reports of a Kremlin 'hit-list', prominent Russian dissidents no longer feel safe, even in Kensington.
Putin critic Alexei Navalny also wants sanctions imposed on Arsenal FC shareholder Alisher Usmanov.
Navalny's release comes a week after fellow critic Boris Nemtsov was murdered in an alleged political killing.
The protest will go on despite Navalny's recent imprisonment meaning he can't attend.
Navalny was jailed for 15 days for breaching a law that restricts demonstrations, barring him from a planned rally on March 1.
Alexei Navalny says the conviction for theft is politically motivated.