Army (800 men) and PMO volunteers (500 men). On August 27, the Poles officially demanded that Lithuanians retreat behind the Foch Line. On September 1, Rudnicki announced incorporation of PMO volunteers into the 41st Infantry Regiment. During the negotiations on September 5, representatives of the two groups agreed to settle on a detailed demarcation line; Lithuanians agreed to retreat by September 7. The Polish regular army units did not cross the Foch Line, and refused to aid the PMO insurgents still operating on the Lithuanian side. Polish sources give total Polish casualties for the Sejny Uprising as 37 killed in action and 70 wounded. Aftermath After the uprising, Poland repressed Lithuanian cultural life in Sejny. Lithuanian schools in Sejny (which had some 300 pupils) and surrounding villages were closed. The local Lithuanian clergy were evicted, and the Sejny Priest Seminary relocated. According to the Lithuanians, the repressions were even more far-reaching, including a ban on public use of the Lithuanian language and the closing of Lithuanian organizations, which had a total of 1,300 members. The New York Times, reporting on renewed hostilities a year later, described the 1919 Sejny events as a violent occupation by the Poles, in which the Lithuanian inhabitants, teachers, and religious ministers were maltreated and expelled. Polish historian Łossowski notes that both sides mistreated the civilian population and exaggerated reports to gain internal and foreign support. The uprising contributed to the deterioration of the Polish–Lithuanian relations and further discouraged the Lithuanians from joining the proposed Międzymorze federation. The Sejny Uprising doomed the Polish plan to overthrow the Lithuanian government in a coup d'état. After the uprising, the Lithuanian police and intelligence intensified their investigation of Polish sympathizers and soon uncovered the planned coup. They made mass arrests of Polish activists from August 27 to the end of September 1919. During the investigations, lists of PMO supporters were found; law enforcement completely suppressed the organisation in Lithuania. Hostilities over the Suwałki Region resumed in summer 1920. When the Polish Army began to retreat during the course of the Polish–Soviet War, the Lithuanians moved to secure what they claimed to be their new borders, set by the Soviet–Lithuanian Peace Treaty of July 1920. The Peace Treaty granted Sejny and surrounding area to Lithuania. Poland did not recognize this bilateral treaty. Ensuing tensions heightened until the outbreak of the Polish–Lithuanian War. Sejny changed hands frequently until it was controlled