Malaysiandigest: As the 47 member body prepared to iron out a draft resolution on the issue, Zeid said that the ancient city of Aleppo, "a place of millennial civility and beauty, is today a slaughterhouse - a gruesome locus of pain and fear, where the lifeless bodies of small children are trapped under streets of rubble and pregnant women deliberately bombed".
"The collective failure of the international community to protect civilians and halt this bloodshed should haunt every one of us," he admonished, adding that "its costs will be borne by our children, and future generations".
But Zeid also said that the civil war had now become a "proxy conflict, fuelled by cynical regional and international interests", killing well over 300,000, besides wounding and traumatizing countless others, leading to abduction, summary executions or arbitrary detention of tens of thousands and displaced more than half of the Syrian population.
By deliberately and repeatedly attacking hospitals, schools, marketplaces, water facilities and neighbourhood bakeries, millions being denied life-saving aid.
Revealing that his Office (OHCHR) had documented multiple violations of international humanitarian law by all parties in Aleppo, Zeid said the attacks that had caused a number of civilian casualties constituted war crimes.
"And if knowingly committed as part of a widespread or systematic attack directed against civilians, they constitute crimes against humanity," he observed, adding that though the responsibility for halting the Syrian crisis primarily lay with the UN Security Council, the General Assembly could also have a role to play.
Highlighting the continuing human suffering, he called on the HRC members to set aside their political disagreements, and concentrate only on the suffering of women, men and children. "No hypothetical advantage in global gamesmanship could possibly outweigh this pain and horror," he said.
Alluding to the rivalries among the Security Council members, he called on them to set aside rivalries and act as one, adding that "influence must be used to advance a political solution to the conflict. Flows of arms and equipment to the parties to the conflict must cease".
He emphasised the urgency of referring the situation in Syria to the International Criminal Court, and said that all parties to the conflict "must know that they will be held accountable for the international crimes they commit - all, without selective protection or discrimination".
Calling for an "immediate, prolonged and all-encompassing ceasefire to enable humanitarian aid" he urged the top UN human rights body to "speak with one voice" for the protection of civilians in what he described as the "defining human rights crisis of our era."
The Human Rights Council's special session was held in the aftermath of Secretary-General Ban Ki-moon's and his Special Envoy, Staffan de Mistura, having briefed an informal meeting of the General Assembly in New York, where Ban contended that the horrors committed in the Syrian conflict may amount to war crimes.
He appealed to Member States "to cooperate and fulfil your collective responsibility to protect."
Ban had also welcomed Russia's latest unilateral announcement of a humanitarian pause to the bombing in eastern Aleppo, but emphasised that the nationwide ceasefire must be revived.
Un agencies maintain that the offensive undertaken by the Syrian Government in eastern Aleppo since Sept 23 was the most sustained and intensive aerial bombardment since the conflict began.
Nearly 500 people have been killed and nearly 2,000 injured, with more than a quarter of all deaths being children. No UN convoy has entered eastern Aleppo since July 7.