On September 17, 1939 the territory of Western Belarus became part of the Soviet Union, what was the beginning of repressions against the spiritual leaders of all faiths including Jews. By February 1, 1940 there were 387 operating synagogues in Western Belarus. It was around the time when authorities began not only shutting down synagogues and yeshivas, but they started arresting and sending spiritual leaders of communities to Siberia. Over 50 Rabbis were sent to Siberia in 1 year. The teaching of the Torah was banned under threat of arrest. Those spiritual leaders who stayed in Western Belarus were forced to switch their occupation. Some of them became vendors, watchmen, cabmen, etc. Despite the repressions, underground Torah study continued in many towns and shtetls of Western Belarus until the beginning of WW2.
The former building of the Mir Yeshiva that was established in 1847. Currently used now as a post office.
Below is the list of spiritual leaders of Jewish communities who continued living in Western Belarus in 1940:Духовные руководители -pdf