A/HRC/37/72 attack, including women and children. Photos of remnants provided by interviewees indicated that RBK-250 and RBK-500 cluster bombs were used. The use of cluster munitions in civilian populated areas is inherently indiscriminate (given their typically wide dispersal pattern and high dud rate, which continue to endanger civilians years after the cessation of hostilities). They are therefore prohibited by customary international humanitarian law. Their use by pro-Government forces in Dayr al-Zawr city constitutes the war crime of indiscriminate attacks in a civilian populated area. V. Internally displaced persons 57. At least 6.5 million Syrians have been displaced within the Syrian Arab Republic as a result of hostilities, including almost 3 million children. Well over one million Syrian civilians were displaced in 2017. Displacement comes in many forms. In some instances, pro-Government forces have repeatedly attacked civilian infrastructure in besieged areas, leading to the displacement of civilians who were able to flee, and thousands of civilians have been forcibly displaced in the framework of reconciliation, which often entails local truces and evacuation agreements.15 58. Many civilians who were forcibly displaced from opposition-held areas found themselves accommodated in schools in Idlib, which were ill-prepared to receive them. Others had no choice but to reside in overcrowded camps or unfamiliar towns, where they lacked basic resources. In Idlib and the neighbouring Aleppo countryside, internally displaced persons live under near-constant bombardment (see paras. 77–79) and do not receive sufficient humanitarian aid. Pursuant to evacuation agreements, pro-Government forces have transferred populations sympathetic to it to areas under Government control in Homs, Tartous and Ladhiqiyah governorates, where conditions are starkly better. 59. In other situations, civilians have been displaced as a result of hostilities or have fled in advance of clashes. Operations against ISIL in Raqqah and Dayr al-Zawr triggered one of the single largest waves of internally displaced persons since 2011. By June 2017, tens of thousands of Syrians from Raqqah and Dayr al-Zawr had begun perilous journeys to escape, crossing frontlines and risking landmines, to relocate to desert camps administered by the Syrian Democratic Forces in northern Raqqah and Hasakah governorates. The total number of persons who fled Raqqah and Dayr al-Zawr stands at 320,000. In northern Raqqah and Hasakah, the Syrian Democratic Forces have interned 80,000 internally displaced persons in order to vet them for possible connections to ISIL. Irrespective of the legitimacy of a security threat, the blanket internment of all internally displaced persons from Raqqah and Dayr al-Zawr by the Syrian Democratic Forces cannot be justified. Among the civilians currently interned are women, children, the elderly and infirm, disabled persons and others who do not represent any imperative security threat and whose continued detention is manifestly unnecessary on any grounds. In many instances, the ongoing internment of those individuals amounts to arbitrary deprivation of liberty and the unlawful detention of thousands of individuals. VI. Returnees and barriers to return 60. In addition to the precarious situation of those who have been internally displaced within the country, up to 600,000 Syrians have returned from abroad and are also internally displaced persons since they could not return to their homes. Throughout Raqqah city, booby traps and landmines planted by ISIL and explosive remnants from airstrikes prevent the feasibility of civilian return. No civilians who had been forcibly displaced to Idlib under local truces and evacuation agreements have returned to their homes. 15 The Commission has previously documented the forcible displacement of civilians by Government forces from eastern Aleppo city (see A/HRC/34/64, para. 93), Madaya (Rif Damascus), Barza, Tishreen and Qabun (eastern Damascus) (see A/HRC/36/55, para. 35) to Idlib governorate. 13