The invasion caused Europe's fastest-growing refugee crisis since World War II,[3][4] with more than 6.5 million Ukrainians fleeing the country[5] and a third of the population displaced.[6][7] On 8 May, Serhiy Haidai, governor of Luhansk Oblast, said on his Telegram channel that the Russians controlled only half of the city of Popasna,[8] but later admitted Ukrainian forces had pulled out.[9] By 12 May, Russian forces had defeated Ukrainian forces in the Battle of Rubizhne and established full control of the city, furthering their attempts at encircling Sievierodonetsk.[10][11]