Moscow has come under the largest Ukrainian attack since the start of the full-scale war, with close to 200 drones hitting targets around the Russian capital and setting columns of thick smoke billowing high into the sky.
Seventeen people were wounded in the Moscow region, according to local governor Andrei Vorobyov.
Almost 1,000 drones and four Ukrainian cruise missiles were intercepted and destroyed across the country in 24 hours, Russia's defence ministry was quoted as saying. An oil depot was struck in the southern Rostov region, where one person was killed.
Volodymyr Zelensky said Kyiv had once again hit the Moscow region with "long-range sanctions" - a euphemism for Ukrainian long-distance strikes on Russia.
"It's time to end this war, and Russia must take the necessary steps in diplomacy," he added.
He said the massive drone strike was in response to last week's Russian attack on Kyiv, which set a major religious landmark ablaze.
"We don't want this war and have never wanted it," Zelensky said. "But if Ukraine burns, your Moscow will burn too."
Fires broke out as the Kapotnya refinery in south-east Moscow was hit for the third time in a month and the second time this week, colouring the sky black with smoke. Numerous videos showed the lid of a large oil storage tank blown dozens of metres into the air by the force of an explosion.
A nearby shopping centre was also burning, reportedly after drone debris fell on the building, and several residential high-rise blocks were evacuated.
Moscow's four airports were temporarily shut and more than 500 flights were cancelled or delayed.
Although local authorities across Russia have banned publication of images of the aftermath of drone strikes, dozens of videos were posted on social media showing drones flying across the sky in broad daylight and explosions over industrial areas on the outskirts of Moscow.
Four and a half years since Moscow launched its full-scale invasion of Ukraine, the war of attrition on the front line in Ukraine grinds on, out of sight for many ordinary Russians.
Kyiv's long-range strikes on targets across Russia as well as Moscow and St Petersburg are an indication of Zelensky's aim of "bringing the war home" to Russians.
Drone attacks on Moscow - about 500km (310 miles) from the Ukrainian border - have become more frequent as Kyiv has developed its long-range capabilities. Ukraine's first successful drone strikes reached the Russian capital in spring 2023, although they were sporadic and rarely involved more than a handful of drones.
Since then, extensive air defences have been set up around Moscow - but the number of drones used by Ukraine in its attacks has also multiplied and some have penetrated those defences.
Meanwhile, Russia launched more than 200 drones and multiple ballistic missiles at Ukraine overnight, Kyiv said.
Vladimir Putin, who is hosting southeast Asian leaders for a summit in the central city of Kazan, has not commented on the large-scale attack on the Russian capital.
Writing on X, Ukrainian Foreign Minister Andriy Sybiha said: "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," Sybiha wrote.
"Now that you know what's going on, ask Putin when he is planning to end it."
