In November 1918 Oskilko led an uprising against the hetman in Volyn. In December he was promoted to colonel of the Ukrainian People's Army. In January 1919 he became a General Khorunzhy and a commander of the North group of the Ukrainian People's Army. On January 5, 1919 his unit, which was passing through Berdichev, perpetrated a pogrom, killing 23 Jews. Oskilko participated in extinguishing the Bolshevik-led Polissya Uprising that was directed against the Directorate of Ukraine and preventing the advancement of the Polish army into Volyn. During that time Rivne became a temporary capital of Ukraine. Due to the strained situation in the region Oskilko suspected that the Ukrainian government and army became infiltrated by the Russian Cheka that sabotaged the frontlines of the Ukrainian army. He also did not trust Petlyura not because of his suspicions, but rather of his believe that Petlyura was weak in character and an unreliable person who became influenced by generals-deserters. On April 12, 1919 a new government was formed headed by Borys Martos replacing the Ostapenko's cabinet. Martos proclaimed the creation of a republic of worker's Councils and intention to conclude a peace treaty with the Bolshevik Russia. Such turn of events made a big impact on the political life of Ukraine. On April 20, 1919 numerous socialists parties of Ukraine entrusted Volodymyr Oskilko to deliver a memorandum to Petlyura for an immediate resignation of the Martos' government. Oskilko handed over the document to Petlyura in Zdolbuniv, who publicly torn it apart. At the end of April 1919 Petlyura twice ordered Oskilko to lead his army to the frontlines against the Bolsheviks. Both orders were never executed. Petlyura then fired the Oskilko's chief of staff, Vsevolod Agapiev, however, Oskilko refused to follow that order as well. On April 28 the Chief Otaman sent him the last order to surrender the command to general Zhelikhovski. On April 29, 1919 Oskilko led a coup-d'etat in Rivne supported by members of the Ukrainian Party of Socialists-Independentists and the Ukrainian People-Republican Party. The participants of the putsch were requesting the appointment of Yevhen Petrushevych as the provisional president of Ukraine until the convocation of Constituent Assembly, transfer of all command to general Omelianovych-Pavlenko and dismiss Symon Petlyura with Andriy Makarenko from organization of military affairs, organization of a coalition government from the members of both Ukrainian republics. Oskilko also sent his representative to Poland with an intent to conduct peace talks. Oskilko reentered politics in late 1922 as an agent of the Polish government in Volhynia, during which time he tried to break up a Jewish-Ukrainian coalition in the Polish parliamentary elections of that year. His campaign was criticized for its usage of antisemitic tropes. Oskilko was assassinated in Rivne in 1926.
