The country’s communications regulators have required Facebook, Twitter and YouTube to remove material that the officials determined was objectionable, with only YouTube, owned by Google, resisting. The video-sharing site complied with a Russian agency’s order to block a video that officials said promoted suicide. But YouTube filed a lawsuit in Russian court in February saying the video, showing how to make a fake wound with makeup materials and a razor blade, was intended for entertainment and should not be restricted. Supporters of the law, which took effect in November, say it is a narrowly focused way of controlling child pornography and content that promotes drug use and suicide. But opposition leaders have railed against the law as a crack in the doorway to broader Internet censorship. They say they worry that social networks, which have been used to arrange protests against President Vladimir V. Putin, will be stifled.