In December 1947, immediately following the UN partition vote, the 1947–1948 Civil War in Mandatory Palestine broke out between the Yishuv and Palestinian Arabs. The Irgun fought together with the Haganah and Lehi during that period. Notable operations in which they took part were the battles of Jaffa and the Jordanian siege on the Jewish Quarter in the Old City of Jerusalem. The Irgun's most controversial operation during this period, carried out alongside Lehi, was an assault on the Arab village of Deir Yassin in which more than a hundred villagers and four of the attackers were killed. The event later became known as the Deir Yassin massacre, though Irgun and Lehi sources would deny a massacre took place there. Begin also repeatedly threatened to declare independence if the Jewish Agency did not do so.