An underground organization created in 1942 in the Bialystok Ghetto. It organized escapes from ghetto, gathered weapon, and prepared to armed resistance against Germans. Starting from February 1943 it conducted many attacks on German troops operating in the ghetto. On August 16, 1943, when the ghetto faced the final liquidation it raised an uprising, commanded by Mordechaj Tenenbaum and Daniel Moszkowicz. After a few days of isolated resistance the uprising fell and both commanders died, probably by their own hand.