The Palestinian Association for Human Rights - Witness has called for an investigation into the deadly airstrike at the Yarmouk refugee camp, south of Damascus. Syrian warplanes targeted the Abdulkader al-Husseini mosque at the camp leaving 20 people dead and dozens injured. The mosque was used as a shelter by Palestinian and Syrian families fleeing from the battle zones. In a statment, the Palestinian Association for Human Rights - Witness condemned the attack and said Palestinian refugee camps are \"civilian zones\" protected under United Nations resolutions and International Humanitarian Law. \"The deliberate targeting of civilians may constitute a war crime in accordance with the Rome Statute of 2002,\" the statement said. The human rights group also demanded that Syrian regime and loyalist forces immediately cease casting the camps into armed conflicts and adhere to the rules of engagement that forbid the targeting of civilians. Witness also demanded a United Nations intervention to protect residents in Syria’s refugee camps and launch an “immediate and transparent” investigation into the circumstances of the airstrike. The organisation called on the United Nations Relief and Works Agency (UNRWA) to \"perform its humanitarian role on a larger scale.\" UNRWA, the statement said, is the only international body capable of delivering humanitarian aid to the Palestinian refugees in Syria, adding that the agency’s failure to perform this role could result in \"major humanitarian disasters.\"