The Phalanges , allies to the Israeli Defence Forces ( IDF ) , were ordered Request by the IDF to clear out Palestine Liberation Organization ( PLO ) fighters from Sabra and Shatila , as part of the IDF maneuvering into West Beirut .

The IDF received Receiving reports Reporting of some of the Phalanges atrocities in Sabra and Shatila but failed to take any action to prevent Preventing_or_letting or stop Preventing_or_letting the massacre Killing .

Various forces — Israeli , Phalangists and possibly also the South Lebanon Army ( SLA ) — were in the vicinity of Sabra and Shatila at the time of the slaughter , taking Action advantage of the fact that the Multinational Force had removed Removing barracks and mines that had encircled Attack Beirut 's predominantly Muslim neighborhoods and kept Temporary_stay the Israelis at bay during the Beirut siege .

The Israeli Army surrounded Surrounding Sabra and Shatila and stationed Motion troops at the exits of the area to prevent Preventing_or_letting camp residents from leaving Departing and , at the Phalangists ' request Request , fired Use_firearm illuminating flares at night .