Russia invaded Ukraine on 24 February 2022, marking a major escalation of the Russo-Ukrainian War, which began following the 2014 Ukrainian Revolution of Dignity. The invasion was internationally condemned as an act of aggression, and has triggered Europe's largest refugee crisis since World War II, with more than 4.6 million Ukrainians leaving the country and a quarter of the population displaced. Following the start of the Russo-Ukrainian War in 2014, Russia had annexed Crimea, and Russian-backed separatists seized part of the south-eastern Donbas region of Ukraine, sparking a war there. In 2021, Russia began a large military build-up along its border with Ukraine, amassing up to 190,000 troops along with their equipment. In a broadcast shortly before the invasion, Russian president Vladimir Putin espoused irredentist views, questioned Ukraine's right to statehood, and falsely accused Ukraine of being governed by neo-Nazis who persecute the ethnic Russian