NATO member Poland said it scrambled aircraft early on Sunday to ensure its air safety after Russia launched airstrikes on Ukraine, with Ukrainian officials reporting missiles and drones raining down on the Lviv region near the Polish border.

"Polish and allied aircraft are operating in our airspace, while ground-based air defence and radar reconnaissance systems have been brought to the highest state of readiness," Poland's operational command said in a post on X.

Eastern-flank NATO members are on high alert after Poland shot down suspected Russian drones in its airspace in September and drone sightings and air incursions, including in Copenhagen and Munich, have led to chaos in European aviation.

Lithuania's airport in Vilnius was closed for several hours overnight after reports of a possible series of balloons heading towards the airport late on Saturday.

According to flight tracking service Flightradar24, early on Sunday, commercial flights were using routings typically used when Poland's Lublin and Rzeszow airports near the border with Ukraine were closed.

Reuters could not independently verify the Flightradar24 report.

There were no immediate notices on the U.S. Federal Aviation Administration's website about possible flight disruptions in Rzeszow and Lublin.

ALL OF UKRAINE UNDER THREAT OF ATTACK

All of Ukraine was under air raid alerts for several hours overnight, with Ukraine's Air Force issuing most dire warnings of missile and drone attacks for the Lviv region.

Andriy Sadovyi, the mayor of Lviv - a western Ukrainian city about 70 km (43 miles) from the border with Poland - said the city's air defence systems were engaged heavily in repelling first a drone and then a Russian missile attack.

As of 7:30 a.m (0430 GMT), parts of the city were left without power and public transport was yet to start running, with Sadovyi saying on the Telegram messaging app that it was "dangerous to go out into the streets."

Reuters witnesses said the pounding of what sounded like air defence systems in operation came from all directions.

A late Saturday night attack on the city of Zaporizhzhia, the capital of the broader frontline region of Zaporizhzhia, left one person dead and nine injured, Ivan Fedorov, the regional governor said on Telegram.

"Apartment blocks and private houses were damaged, cars burned," Fedorov said. "Windows were blown out, yards wrecked."

More than 73,000 customers in the southeastern region were left without power, he added.

Some 55 km (35 miles) southwest of the city of Zaporizhzhia, the Russian-held Zaporizhzhia Nuclear Power Plant has been cut off from external power since September 23.

The head of the U.N.'s nuclear watchdog urged Ukraine and Russia on Friday to show the "political will" required to keep the area safe around the plant, Europe's largest, that was seized by Russian forces in the early weeks of Moscow's invasion of Ukraine.

There has been no immediate comment from Russia about the Saturday overnight attacks.

Both sides have been launching air attacks throughout the war aimed at destroying infrastructure deemed crucial to the overall war efforts, including energy and transport facilities.