Russia, for its part, fired missiles into Kyiv, also for the second time in days, following an attack that damaged Kyiv's landmark 1000-year-old monastery and drew international condemnation.
In Moscow on Thursday, Reuters saw flames and plumes of smoke over the densely populated southeastern district of Kapotnya where the refinery supplying the capital is located.
"Air defence forces continue to repel a massive attack. Several drones managed to reach the Moscow oil refinery," Moscow mayor Sergei Sobyanin said, adding that a shopping centre also suffered minor damage.
Russia's defence ministry said 555 drones were shot down across the country.
Sobyanin said 180 were shot down around Moscow alone.
State news agency TASS said the attack on Moscow was one of the biggest of 2026.
More than four years since Russia's full-scale invasion, Ukraine has increasingly been targeting Russia's energy infrastructure with long-range drone strikes, while Russia has continued firing missiles at Ukrainian cities.
After years when Russian forces made slow but relentless gains on the battlefield, Kyiv says its improving drone capabilities are shifting the war's momentum in its favour, providing new impetus for Moscow to agree to a peace deal.
"One of the most popular questions asked by Muscovites this morning is 'What is going on?' I can answer. Your country started a war of aggression against ours. For years, it has been killing our people. Now that you know what's going on, ask Putin when he is planning to end it," Ukrainian Foreign Minister Andrii Sybiha posted on X.
President Volodymyr Zelenskiy called the attacks on Russia a "totally fair response to Russian strikes on our cities and communities and another important result of the work of our soldiers on facilities that provide support for the Russian war machine".
An earlier drone strike on Tuesday on Moscow's refinery had already halted operations there, sources said, adding to widespread damage to Russian energy facilities.
Russia, the world's third-biggest oil producer and a major oil and fuel exporter, is set to import fuel by sea in June as it seeks to manage a petrol shortage following Ukrainian drone attacks on refineries, according to industry sources.
In the surrounding Moscow region, a high-rise residential building, an industrial facility and a number of private houses were also damaged in the drone attack, the regional governor said.
Flights were suspended at all Moscow airports and traffic shut on the highway around the capital near the refinery.
Sheremetyevo airport, Moscow's busiest, said it had been evacuated.
Elsewhere in Russia, officials said a Ukrainian drone strike killed one man in his car in the Belgorod border region, and a Ukrainian drone attack killed one person and caused a fire at two commercial facilities in the southern Rostov region.
In Kyiv, explosions rang out and air strike alerts were issued for most of Ukraine's territory.
Authorities in the northeastern Ukrainian city of Sumy said one person was killed in a drone attack.
On Monday, a major attack on Kyiv by Russia damaged the medieval monastery that symbolises Ukraine's spiritual and cultural heritage, drawing condemnation from European leaders. Russia denied striking it.
Zelenskiy has launched a diplomatic push to increase pressure on Russia to negotiate an end to the war.
Moscow, which says Ukraine is losing, has demanded Kyiv cede additional territory before it will discuss peace.
with Reuters
