The Vilna offensive was a campaign of the Polish–Soviet War of 1919–1921. The Polish army launched an offensive on April 16, 1919, to take Vilnius (Polish: Wilno) from the Red Army. After three days of street fighting from April 19–21, the city was captured by Polish forces, causing the Red Army to retreat. During the offensive, the Poles also succeeded in securing the nearby cities of Lida, Pinsk, Navahrudak, and Baranovichi.

The Red Army launched a series of counterattacks in late April, all of which ended in failure. The Soviets briefly recaptured the city a year later, in spring 1920, when the Polish army was retreating along the entire front. In the aftermath, the Vilna offensive would cause much turmoil on the political scene in Poland and abroad.

As the Polish troops entered the city, the first pogrom in modern Vilnius started. Dozens of people connected with the Lit-Bel were arrested, and some were executed. Jews constituted close to one-half of Vilnius's population, according to the German census of 1916, and many victims of fighting and subsequent repression in Vilnius were Jews. Henry Morgenthau, Sr. counted 65, Joseph W. Bendersky counted over a hundred.

There was a common belief among the Poles that most Jews were Bolsheviks and Communists, in league with the enemy of the Polish state, Soviet Russia. The Polish army stated that any Jews it killed were militants and collaborators engaged in actions against the Polish army. Having been fired at from Jewish homes, Polish soldiers took this as an excuse to break into many Jewish homes and stores, beating the Jews and robbing them, desecrating synagogues, arresting hundreds, depriving them of food and drink for days and deporting them from the city; such abuses were, however, not supported by – and even specifically forbidden by – the Polish high command.

A report of the activities of the Polish Army in Vilnius, noting that 65 Jews with no proven connections to the Bolsheviks had been killed, and that many arrests, robberies and mistreatments had occurred, while soldiers guilty of these acts had not been punished.

Sources:

• https://en.wikipedia.org/wiki/Vilna_offensive