A/HRC/21/50 Shabbiha members acted with the acquiescence of, in concert with or at the behest of Government forces. International human rights law recognizes the responsibility of States that commit violations through proxies. B. Responsibility of anti-Government armed groups 134. Although not a State party to the Geneva Conventions, organized armed groups must nevertheless abide by the principles of international humanitarian law.26 During noninternational armed conflicts, serious violations of international humanitarian law committed by members of such groups are prosecutable as war crimes. Non-State actors may also bear responsibility for gross abuses of human rights, in particular those that amount to international crimes.27 The commission identified such violations, including murder, extrajudicial execution and torture, perpetrated by members of anti-Government groups. C. Individual responsibility 135. Whether members of Government forces or anti-Government groups, those who intentionally commit the crimes identified in the present report bear responsibility. In addition, those who order these crimes to be committed (or plan, instigate, incite, aid or abet) are also liable. The commission received consistent evidence that mid- and highranking members of Government forces were directly involved in illegal acts. Defectors stated that commanders ordered their subordinates to shoot civilians and hors de combat fighters, and to torture and mistreat detainees. Orders were often enforced at gunpoint, and anyone hesitating to comply risked arrest or summary execution. Evidence showed that widespread looting and destruction of property occurred with the acquiescence of commanders. 136. Leadership within anti-Government armed groups was also implicated in the war crimes and human rights abuses detailed in the present report. Local commanders either ordered the execution of captured members of Government forces and the Shabbiha or killed them themselves. D. Command responsibility 137. Military commanders and civilian superiors bear responsibility for crimes against humanity and war crimes if they fail to take reasonable measures within their power to prevent or repress the commission of these crimes or to submit the matter to the competent authorities. These measures must be implemented with respect to subordinates over whom they exercise effective command and control. 138. Extensive coverage of events, including the likely occurrence of violations and crimes, led the commission to conclude that military commanders and civilian superiors at the highest levels of Government must have known about such events. 139. The same applied to abuses and crimes committed by anti-Government armed groups. Local-level commanders acknowledged some of the acts described in interviews. 26 27 22 See annex II, paras. 11–13. See annex II, paras. 8–10.