Ben-Gurion invested Yigael Yadin with the responsibility to come up with a plan of offense whose timing was related to the foreseeable evacuation of British forces . This strategy , called Plan Dalet , was readied by March and implemented towards the end of April . A separate plan , Operation Nachshon , was devised to lift the siege of Jerusalem . 1500 men from Haganah 's Givati brigade and Palmach 's Harel brigade conducted sorties to free up the route to the city between 5 and 20 April . Both sides acted offensively in defiance of the Partition Plan , which foresaw Jerusalem as a corpus separatum , under neither Jewish nor Arab jurisdiction . The Arabs did not accept the Plan , while the Jews were determined to oppose the internationalization of the city , and secure it as part of the Jewish state . The operation was successful , and enough foodstuffs to last two months were trucked into Jerusalem for distribution to the Jewish population . The success of the operation was assisted by the death of al-Husayni in combat . During this time , and independently of Haganah or the framework of Plan Dalet , irregular fighters from Irgun and Lehi formations massacred a substantial number of Arabs at Deir Yassin , an event that , though publicly deplored and criticized by the principal Jewish authorities , had a deep impact on the morale of the Arab population and contributed to generate the exodus of the Arab population
Deir Yassin
Deir Yassin massacre
1948 Arab–Israeli War