Moscow Mayor Sergei Sobyanin said the strikes killed three people and damaged part of an oil refinery on the final day of Russia's first wartime parliamentary elections.
A Russian-installed election commission head said turnout was strong on the first day of a multi-day vote for Russia's State Duma in the Kherson Region, territory Moscow claims to have annexed from Ukraine.
Moscow's remote e-voting system faces scrutiny over security concerns and misinformation during ongoing elections.
Election commission chair Ella Pamfilova said authorities have anticipated many potential threats to the upcoming parliamentary vote.