Navi Pillay, the United Nations high commissioner for human rights, has cited the increasing casualty count in Syria as a basis for an International Criminal Court investigation into war crimes in the nearly two-year-long conflict.

Speaking after a closed meeting of the United Nations Security Council on Friday, Pillay said there was little indication the 15-member body would take action on the 22-month conflict.

"I firmly believe that war crimes and crimes against humanity have been committed, are being committed, and should be investigated," Pillay said citing the UN figure of 60,000 deaths in Syria.