Ukraine carried out its largest drone assault on the Moscow region on Sunday, striking an oil refinery and a logistics facility, according to regional officials.

Mayor Sergei Sobyanin reported that 450 drones were intercepted over the capital, describing the operation as the most extensive of its kind. The governor of the surrounding area confirmed two fatalities and 20 injuries, including three children.

Ukrainian President Volodymyr Zelensky verified that Ukrainian forces hit a major Russian oil installation and a supply hub, stating the damage amounted to billions of dollars in lost revenue that supports military operations. Ukrainian officials also noted civilian deaths in separate Russian strikes on Kyiv and Sumy regions.

The refinery targeted supplies over one-third of the Moscow region's fuel needs, including diesel, petrol and aviation fuel used by Russian military units. Ukraine's defence minister said the attack directly weakens the enemy's capacity to sustain its war effort.

Sobyanin suggested the strike aimed to disrupt Russia's parliamentary elections occurring on Sunday, which critics have condemned as neither free nor fair. Russian state media reported an election official among those killed in a separate drone strike on a bus in Kherson.

Airports in Moscow, including Sheremetyevo and Vnukovo, imposed temporary flight restrictions overnight due to the attacks. Restrictions were lifted by Sunday morning, though delays persisted.

Additional civilian casualties were recorded in Fastiv, where a mother and her two children died in a Russian attack, and in Vyshhorod, where a child injured in a separate strike later succumbed to injuries. In the Sumy region, four people traveling in a vehicle were killed when a Russian drone struck their car.

Zelensky also confirmed a drone hit on a monastery in Kherson, resulting in one clergy member killed and four others injured. Both sides have continued targeting energy infrastructure in recent days, despite former U.S. President Donald Trump's claim that they had agreed to refrain from such attacks.

The United States has indicated it may impose 100% tariffs on major buyers of Russian energy, while Russian President Vladimir Putin launched a full-scale invasion of Ukraine in February 2022.