Chortkiv offensive

The Chortkiv offensive (Чортківська офензива) (7-28 June 1919), sometimes also referred to as the June Offensive, was a surprise military operation by the Ukrainian Galician Army (UHA) on the newly founded Second Polish Republic Polish-Ukrainian War for Eastern Galicia.

The disputed territory was claimed by the nascent Ukrainian state, the Western Ukrainian People's Republic, which also was disputed by the Ukrainian Peoples Republic and the recently re-established Poland. The area claimed between these three groups was a mixture of Polish, Ukrainian, Jewish peoples intermixed throughout the area.

While the initial success of this attack by the Ukrainian force, in the end the offensive was successfully repelled by the numerically superior and battle hardened Polish force that pushed the Ukrainians back. Eventually, the interwar future of entire Galicia was decided at the Allied Council of Foreign Ministers that officially hostilities were ceased, however operations existed all the way to the Zbruch River.

The goals
The goal of the Chortkiv offensive was to push the Polish army back to the Zolota Lypa River in order to improve morale among the Ukrainian army and locals by mobilizing a larger army to push the Poles back past Lvov, Przemysl, Chelm, Lublin, and other claimed territories by the Western Ukrainian Republic.

The offensive
On 8 June the 19,000 strong UHA assaulted the city of Chortkiv, forcing the Poles to retreat to the Holohory–Peremyshliany–Bukachivtsi line. Under the command of Oleksander Hrekov, the Ukrainians came close to Lviv, the main city of the province, which was their greatest success.

The Ukrainian forces also gained victories at Yazlovets (10 June), Buchach (11 June), Pidhaitsi, Nyzhniv and Ternopil (14 June) and Berezhany (21 June).

Polish counterattack
As the UHA suffered from a lack of ammunition, on 28 June a better equipped and trained Polish force broke through the Ukrainian lines at Yanchyn and forced the UHA to retreat to the Zbruch River. Eventually the Ukrainians were forced back toward the Dnipro Valley then controlled by the Ukrainian People's Republic, another nascent Ukrainian state that did not hold the same territorial aspirations as its ethnic neighbor.

Aftermath
Though the UHA initially scored several early victories, the Chortkiv offensive eventually ended in defeat and end of the UHA and its rule over the disputed eastern and western provinces of the former Austrian Galicia.