In her opening speech to the UNHRC's emergency summit in Geneva, Ms Pillay said there were "strong reasons to believe that both sides have grossly disregarded the fundamental principle of the inviolability of civilians".

She said an "independent and credible international investigation" should be carried out to establish "the occurrence, nature and scale of violations of international human rights and international humanitarian law, as well as specific responsibilities".

"Establishing the facts is crucial to set the record straight regarding the conduct of all parties in the conflict," she said.