In March 1943, about 4,075 Jews living in Bulgarian-occupied eastern Greek Macedonia and Western Thrace (annexed as the Bulgarian province of Belomorie) were deported to Treblinka extermination camp and murdered. In an operation coordinated by Bulgaria and Germany, almost all Jews in Bulgarian-occupied Greece were rounded up on the early morning of 4 March 1943, held in camps in Bulgaria, and reached Treblinka by the end of the month. The death rate of 97 percent of the Jews living in the area in 1943 was one of the highest in Europe.