On December 9, 1918, Ukrainian forces broke through the outer defences of Przemyśl in the hope of capturing the city and thus cutting off Polish-controlled Lviv from central Poland. However, the Poles were able to quickly send relief troops and by December 17 the Ukrainians were forced back. On December 27, bolstered by peasant troops sent to Galicia from Eastern Ukraine in the hopes that the Western Ukrainians would be able to form a disciplined force out of them, a general Ukrainian offensive against Lviv began. Lviv's defences held, and the eastern Ukrainian troops mutinied.