The Russian 1st Cavalry Army under Semyon Budyonny broke through Polish lines in early June. The effects of that were dramatic; Budyonny's success resulted in a collapse of all Polish fronts. On July 4, Mikhail Tukhachevsky's Western Front began an all-out assault in Belarus from the Berezina River, forcing Polish forces to retreat. On July 19 the Red Army seized Grodno and on July 28, it reached Białystok. On July 22, the Brześć Fortress was captured. In early August, Polish and Soviet delegations met at Baranavichy and exchanged notes, but their talks came to nothing.