MOSCOW -- A Moscow court has ruled in favor of Kremlin-connected oligarch Alisher Usmanov in his defamation lawsuit against opposition politician and anticorruption activist Aleksei Navalny.

After two days of hearings, Judge Marina Vasina of the Lyubinsky district court on May 31 ordered Navalny to remove from the Internet all publications that mention Usmanov and to publish a retraction within 10 days. She added that the retraction must remain on Navalny's website for three months.

Georgy Alburov, head of the investigations department of Navalny's Anticorruption Foundation, said on Twitter that "we will not delete anything."

During the hearing earlier in the day, Navalny told the judge he would not voluntarily remove any material. He also said he would appeal a decision against him to higher courts in Russia and, if necessary, to the European Court of Human Rights.

Speaking to journalists after the ruling, Navalny said he didn't expect any other outcome and that he would not delete anything regardless of the decision of the appeals courts.

"If the legal system defends such criminality and theft, it means we must fight against that system even harder," he said. Navalny added that he expects the ruling will increase participation in a nationwide anticorruption protest that he is organizing on June 12.

Usmanov filed the suit in April after Navalny released a video alleging massive corruption on the part of Prime Minister Dmitry Medvedev using a network of purported charitable foundations to control wealth both in Russia and abroad.

One of the allegations was that Usmanov gave a $50 million mansion outside Moscow to one of Medvedev's foundations "as a gift." Usmanov has said he traded the property for one of equal value and that he has no idea what has become of it since that time.

Under the court's ruling, Navalny would have to delete the video, which has been viewed more than 20 million times since it was posted in March.

Navalny will also have to delete and retract other claims involving Usmanov, including the allegations that he has given bribes, was a criminal, did not pay taxes in Russia, and participated in the illegal privatization of state mining concerns.

Navalny has said the aim of the suit was to distract attention from the allegations against Medvedev.

Navalny is attempting to mount a campaign for Russia's 2018 presidential election, in which President Vladimir Putin is widely expected to seek a fourth term.

Russian authorities have suggested that Navalny would be barred from the presidential ballot due to a conviction on financial-crimes charges he contends were fabricated.

But election officials have not stated clearly whether Navalny will be allowed to run, and he has pushed ahead with his campaign.

With reporting by Dozhd TV, Meduza, and Novaya Gazeta