A/HRC/12/48 (ADVANCE 2) page 18 1953. The Mission also examined whether the Palestinian armed groups complied with their obligations under international humanitarian law to take constant care to minimize the risk of harm to the civilian population in Gaza among whom the hostilities were being conducted. The conduct of hostilities in built-up areas does not, of itself, constitute a violation of international law. However, launching attacks – whether of rockets and mortars at the population of southern Israel or at the Israeli armed forces inside Gaza – close to civilian or protected buildings constitutes a failure to take all feasible precautions. In cases where this occurred, the Palestinian armed groups would have unnecessarily exposed the civilian population of Gaza to the inherent dangers of the military operations taking place around them. The Mission found no evidence to suggest that Palestinian armed groups either directed civilians to areas where attacks were being launched or that they forced civilians to remain within the vicinity of the attacks. The Mission also found no evidence that members of Palestinian armed groups engaged in combat in civilian dress. Although in the one incident of an Israeli attack on a mosque it investigated the Mission found that there was no indication that that mosque was used for military purposes or to shield military activities, the Mission cannot exclude that this might have occurred in other cases. 5. Actions by responsible Palestinian authorities 1954. Although the Gaza authorities deny any control over armed groups and responsibility for their acts, in the Mission’s view, if they failed to take the necessary measures to prevent the Palestinian armed groups from endangering the civilian population, the Gaza authorities would bear responsibility for the damage arising to the civilians living in Gaza. 1955. The Mission finds that security services under the control of the Gaza authorities carried out extrajudicial executions, arbitrary arrests, detentions and ill-treatment of people, in particular political opponents, which constitute serious violations of the human rights to life, to liberty and security of the person, to freedom from torture or cruel, inhuman or degrading treatment or punishment, to be protected against arbitrary arrest and detention, to a fair and impartial legal proceeding; and to freedom of opinion and expression, including freedom to hold opinions without interference. 1956. The Mission also concludes that the Palestinian Authority’s actions against political opponents in the West Bank, which started in January 2006 and intensified during the period between 27 December 2008 and 18 January 2009, constitute violations of human rights and of the Palestinians’ own Basic Law. Detentions on political grounds violate the rights to liberty and security of person, to a fair trial and the right not to be discriminated against on the basis of one’s political opinion, which are all part of customary international law. Reports of torture and other forms of ill-treatment during arrest and detention and of death in detention require prompt investigation and accountability. K. The need for accountability 1957. The Mission was struck by the repeated comment of Palestinian victims, human rights defenders, civil society interlocutors and officials that they hoped that this would be the last investigative mission of its kind, because action for justice would follow from it. It