Poland’s military has said that a Russian missile fired at Ukraine briefly entered its airspace on Sunday. Warsaw has placed its forces on heightened readiness. Kyiv and Ukraine’s western Lviv region came under a “massive” Russian air attack early morning Sunday, Ukrainian officials said. Ukraine said it intercepted 18 Russian missiles and 25 drones during the large-scale attack on the country’s capital, with an air alert lasting more than two hours. There were no immediate reports of casualties, according to the head of Kyiv’s military administration, Serhiy Popko. “The enemy continues massiv…