Russia has targeted Ukraine with a record 728 drones, hours after United States President Donald Trump pledged to send more defensive weapons to Kyiv and aimed unusually sharp criticism at Russian President Vladimir Putin.
The attack overnight was the latest in a series of escalating air assaults in recent weeks that have involved hundreds of drones in addition to ballistic missiles, straining Ukrainian air defences at a perilous moment in the war.
Ukraine's military downed almost all the drones, but some of the six hypersonic missiles launched by Russia had caused unspecified damage, air force spokesperson Yurii Ihnat said on Ukrainian television.
Officials reported one person killed by drone debris in western Ukraine.
Russia's defence ministry said it had struck military airfields.
Closer to the battle zone, eight people were reported killed by drones and guided bombs in the Ukrainian-held part of the frontline Donetsk region.
Ukrainian President Volodymyr Zelenskyy, who is due to meet US envoy Keith Kellogg in Rome ahead of a gathering of countries friendly to Ukraine, said the strike showed the need for "biting sanctions" on Russia's income, including on countries that buy Russian oil.
Zelenskyy also met Pope Leo, who offered to host peace talks at the Vatican. Zelenskyy said this would be "entirely possible" but that it had so far been rejected by Russia.
Trump said on Wednesday AEST he was considering supporting a bill that would impose steep sanctions on Russia, including 500 per cent tariffs on nations that buy Russian oil, gas, uranium and other exports.
"We get a lot of bullshit thrown at us by Putin ... He's very nice all the time, but it turns out to be meaningless," Trump said at a cabinet meeting.
When asked by a reporter what action he would take against Putin, Trump said: "I wouldn't tell you. We want to have a little surprise."
Separately, the European Union is working on a new sanctions package against Russia.
Trump, who returned to power this year promising a swift end to the war that started in 2022, has taken a more conciliatory tone towards Russia in a departure from his predecessor Joe Biden's administration's staunch support for Ukraine.
But initial rounds of talks between Russia and Ukraine have so far borne little fruit, with Russia yet to accept an unconditional ceasefire proposed by Trump and accepted by Ukraine.
Trump's promise to supply more defensive weapons appeared to reverse a Pentagon decision days earlier to stall some critical munitions supplies to Ukraine, despite Russian attacks that have killed dozens in recent weeks.
Shortly after the attack, German Chancellor Friedrich Merz said diplomatic means to resolve the war had been exhausted. He vowed to continue supporting Ukraine.
Merz said he would make an offer of air defence systems to Ukraine at the conference in Rome.
Residents of Kyiv and other major cities spent the night in air raid shelters, including metro stations.
Part of Russia's overnight strike was aimed at a western region close to NATO-member Poland. The north-western city of Lutsk, some 200km from Poland, was the main target, Zelenskyy said, listing 10 other provinces across Ukraine where damage was also reported.
Polish and allied aircraft were activated to ensure air safety, Poland's military said.
