Navi Pillay, United Nations High Commissioner for Human Rights, tells Al Jazeera that violence in Syria is being fuelled by the increasing flow of weapons to both sides in the conflict.

Pillay says huge numbers of people in detention, the cutoff of humanitarian aid by fighting on the ground, and the lack of access to investigators and journalists has led to a "deteriorating situation" in Syria.

The UN rights chief also says "it's time for the Security Council to act in the matter" and refer the "perpetrators of these egregious crimes" for investigation by the International Criminal Court (ICC), where they could face charges of crimes against humanity.