At least three people were injured and multiple fires erupted in Kyiv early Sunday following a Russian missile strike, according to the city's mayor and military administration, News.Az reports citing Reuters.
All of Ukraine was under air alerts as of 0200 GMT after the country's air force warned of an attack including on regions bordering Poland, forcing the NATO-member to scramble aircraft to ensure air safety.
"Do not leave shelters!" Klitschko said.
Reuters' witnesses heard several loud explosions in what they said sounded like air defence units in operation.
The scale of the attack was not immediately clear. There were also no reports of strikes or damage in western Ukrainian regions that border Poland.
