At least three people have been killed and more than 30 injured in a "massive" overnight Russian aerial attack on Ukraine, President Volodymyr Zelensky says.

He says regions across the country were targeted as part of a "deliberate strategy" to "intimidate civilians and destroy our infrastructure", with one direct missile hit reported on a residential building.

Ukraine's air force says Moscow launched 619 drones and missiles. Russia's defence ministry says its "massive strike" used "precision weapons" and targeted military-industrial facilities.

Separately, Russia says four people were killed in a Ukrainian drone attack on the Saratov region. Kyiv says it hit a major oil refinery there.

Ukraine also says another Russian oil refinery was damaged in the neighbouring Samara region.

The BBC has been unable to independently verify the claims made by the two warring sides.

Cross-border drone raids have become a prominent feature of the war. In July, a sustained Ukrainian drone attack forced the temporary closure of all of Moscow's airports.

Kyiv has been systematically targeting Russian oil and other key industrial facilities, which play a key role in Russia's continuing war effort in Ukraine.

Meanwhile, Moscow has in recent weeks escalated its aerial assaults on Ukraine, while Kyiv and its Western allies - including the US - continue to call for a ceasefire.

Earlier this month, the main government building was hit in Ukraine's capital Kyiv by what Ukraine said was a Russian Iskander cruise missile.

Zelensky said on Saturday that he planned to meet US President Donald Trump on the sidelines of the United Nations General Assembly (UNGA), taking place in New York next week.

Trump hosted Russian President Vladimir Putin in Alaska last month, hoping to secure a deal on ending the conflict. No such agreement was made.

Putin launched a full-scale invasion of Ukraine in 2022.

The latest Russian aerial attack comes a day after Estonia requested urgent consultations with other Nato members after Russian jets violated its airspace - staying there for 12 minutes before being intercepted.

Russia denied violating Estonian airspace.

Tensions have been escalating recently after Poland and Romania - both Nato members - said Russian drones breached their airspace earlier this month.