What to know

• Ukraine launched what Moscow's mayor called the biggest drone attack yet on the Russian capital on Sunday, as Russians voted on the final day of a parliamentary election.S1
• Plumes of smoke rise from fires at an oil refinery following what the authorities say is a Ukrainian drone strikeS2
• The largest Ukrainian drone attack reported so far on the Moscow region killed two people ⁠and damaged part of an oil refinery in the capital, authorities said Sunday.S3