In mid-1941, Greece was partitioned into different occupation zones by Germany, Italy, and Bulgaria. Germany occupied strategically important areas, including Salonica and the surrounding area and a strip of land along what had been Greece's border with Turkey. Western Thrace and eastern Macedonia were annexed as the Bulgarian province of Belomorie, where Bulgaria immediately undertook a harsh Bulgarianization program. Bulgaria executed 40,000 Greeks during the occupation—more than Germany and Italy combined—including 2–3,000 during the brutal suppression of the 1941 Drama uprising. About 100,000 Greeks were forced to flee westward and the overall population fell by 217,000 by 1942 despite mass immigration of Bulgarian settlers.