NATO was forced to scramble fighters as Russia launched a massive missile and kamikaze drone attack on Ukraine.
At least 11 people were killed and 46 others injured, including five children, after houses were blitzed in the overnight strikes on Kyiv.
Russia launched 68 missiles and 351 drones at Ukraine, Kyiv’s air force said on Monday.
Air defence units shot down or neutralised 37 missiles and 326 drones, it added.
A Russian strike hit a suspected missile warehouse in Holosiivskyi district triggering massive secondary blasts.
An urgent evacuation was ordered in Vyshneve amid the threat of more detonations and toxic smoke.
Hours earlier Ukrainian President Volodymyr Zelensky said intelligence indicated a huge strike ordered by Russian tyrant Vladimir Putin was imminent.
“Russia wants to bring more evil and kill people. Please stay safe and heed any air raid alerts,” he warned Ukrainians.
The savage strikes came on the eve of the NATO summit in Ankara, which Western leaders including Donald Trump and outgoing UK Prime Minister Sir Keir Starmer will attend.
A statement from Poland’s armed forces operational command said: “Due to the activity of the long-range aviation of the Russian Federation, which strikes the territory of Ukraine, military aviation has begun operations in Polish airspace.”
The NATO military response was “preventive” over Poland, which borders Ukraine.
“Fighters started the operation, and ground air defence systems and radio-location recognition have reached alert.”
Images emerging from Kyiv show the charred remains of burnt out cars and crumbling buildings throughout the city.
Footage also shows crews combing through wreckage on Monday morning to find survivors.
Authorities have warned the death toll could continue to climb as rescue missions continue.
Among the targets was a building of the Kyiv Roshen Confectionery Factory, owned by former Ukrainian president Petro Poroshenko.
In Kyiv’s Podilskyi district, there were fires at four different residential buildings.
People were trapped inside at least one of the buildings with the fifth to the ninth floors destroyed.
An entire family – a mother, father and son – were killed, say reports.
Kyiv Regional Military Administration Mykola Kalashnyk said of the missile plant strike: “The most difficult situation is in Vyshneve of Bucha district.
“Due to the threat of repeated detonation of explosive objects, staying near the strike site is extremely dangerous.
“The territory is surrounded by police. I urge residents of the community to remain in safe places and not to approach the area where operations are underway.
“Police officers and rescuers are conducting evacuations as needed.”
Overnight Ukrainian attacks once more hit a key oil refinery in Yaroslavl, supplying Moscow amid chronic fuel shortages.
The key Kerch port in occupied Crimea was also attacked with an oil and gas terminal ablaze.