Russia invaded Ukraine on 24 February 2022, marking a steep escalation of the Russo-Ukrainian War, which began in 2014 following the Ukrainian Revolution of Dignity. The invasion has caused Europe's largest refugee crisis since World War II, with more than 5.5 million Ukrainians leaving the country and a quarter of the population displaced.At the start of the war in 2014, Russia annexed Crimea, and Russian-backed separatists seized part of the south-eastern Donbas region of Ukraine, sparking a regional 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 televised address 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 minority. Putin also said the North Atlantic Treaty Organization (NATO) constitutes a threat to Russia's national security by expanding eastward since the early 2000s, which NATO disputed. Russia demanded NATO cease expansion and...