In spring of 1940, Western Europe was overrun by Nazi Germany. With world attention focused on those events, on June 26, 1940, the USSR issued a 24-hour ultimatum to Romania, demanding immediate cession of Bessarabia and Northern Bukovina under threat of war. Romania was given four days to evacuate its troops and officials. The two provinces had an area of , and were inhabited by about 3.75 million people, half of them Romanians, according to official Romanian sources. Two days later, Romania yielded and began evacuation. During the evacuation, from June 28 to July 3, groups of local Communists and Soviet sympathizers attacked the retreating forces, and civilians who chose to leave. Many members of the minorities (Jews, ethnic Ukrainians and others) joined in these attacks. The Romanian Army was also attacked by the Soviet Army, which entered Bessarabia before the Romanian administration finished retreating. The casualties reported by the Romanian Army during those seven days consisted of 356 officers and 42,876 soldiers dead or missing.