Warsaw – Saint Petersburg Railway and second, the Suwałki Region, including the towns of Sejny, Suwałki, Puńsk, was assigned to Poland. Despite assurances at the time that the line was just a temporary measure to normalize the situation before full negotiations could take place, the southern Foch Line is the present-day Lithuania–Poland border. On July 26, the Foch Line was accepted by the Conference of Ambassadors as the provisional border between the two states. Lithuanians were not informed about this decision until August 3. Neither country was satisfied: both Lithuanian and Polish forces would have to retreat from the Suwałki and Vilnius regions, respectively. Those Germans still present in the region also objected to the boundary of the line. The Lithuanian forces (about 350 strong) left the town of Suwałki by August 7, but stopped in Sejny and formed a line at the Czarna Hańcza river – Wigry Lake, thus effectively violating the demarcation line. Lithuanians believed that the Foch Line was not the final decision, and that they had the duty to protect Lithuanian outposts in the region. Uprising preparations On August 12, 1919, two days after the Germans retreated from Sejny, a Polish meeting in the town attracted over 100 delegates from neighboring Polish communities; the meeting passed a resolution that "only securing the area by Polish Army can solve the problem." The Sejny branch of the Polish Military Organization (PMO), led by Polish regular army officers Adam Rudnicki and Wacław Zawadzki, began preparing for the uprising on August 16. PMO members and local militia volunteers numbered some 900 or 1,200 men (sources vary). The uprising was scheduled for the night of August 22 to 23, 1919. The date was chosen to coincide with the withdrawal of German troops from the town of Suwałki. The Poles hoped to capture the territory up to the Foch Line and advance further to take control of the towns of Seirijai, Lazdijai, Kapčiamiestis as far as Simnas. According to the Polish historian Tadeusz Mańczuk, Piłsudski – who was planning a coup d'état in Kaunas – discouraged the local PMO activists from carrying out the Sejny Uprising. Piłsudski reasoned that any hostilities could leave Lithuanians even more opposed to the proposed union with Poland (see Międzymorze). The local PMO disregarded his recommendations and launched the uprising. While locally successful, it led to the failure of the nationwide coup. On August 17, a Lithuanian