 On September 22, 1920, Poland attacked Lithuanian units in the Suwałki Region as part of the Battle of the Niemen River. The Polish army took prisoner 1,700 Lithuanian troops who had surrendered. Polish forces then marched, as planned during the September 8 meeting, across the Neman River near Druskininkai and Merkinė to the rear of the Soviet forces near Hrodna and Lida. The Red Army retreated. This attack, just two days after the League's resolution, damaged both Poland's and the League's reputation. Some politicians began to view Poland as an aggressor while the newly formed League realized its own shortcomings in light of such defiance. On September 26, urged by the League, Sapieha proposed new negotiations in Suwałki. Lithuania accepted the proposal on the following day.
