The United Nations secretary-general on Monday demanded the immediate implementation of 30-day ceasefire in Syria as the Damascus regime continued its deadly bombardment of the rebel-held Eastern Ghouta.
UN chief Antonio Guterres praised the adoption of a Security Council resolution on Saturday calling for the truce but underscored "Security Council resolutions are only meaningful if they are effectively implemented.
"That is why I expect the resolution to be immediately implemented and sustained," he told the opening of the 37th session of the UN Human Rights Council in Geneva.
Addressing the rights council after Guterres, UN human rights chief Zeid Ra'ad Al Hussein said that Syria – and other conflict zones – had "become some of the most prolific slaughterhouses of humans in recent times."
On the proposed Syria truce, Zeid warned that "we have every reason to remain cautious."
The resolution "must be viewed against a backdrop of seven years of failure to stop the violence, seven years of unremitting and frightful mass killing."
Fresh bombardment by the Syrian regime killed at least 10 civilians in Eastern Ghouta on Monday, including nine members of a same family, the Syrian Observatory for Human Rights monitor group said.
Air strikes destroyed a building in Douma, the main town in the Eastern Ghouta area east of Damascus, and buried alive an entire family, according to the Observatory.
More than 500 civilians have been killed in regime and Russian bombardment on the enclave, which is controlled by Islamist and jihadist fighters, since February 18, the Observatory further said.
Zeid has repeatedly and forcefully chastised the Security Council throughout the Syrian conflict for failing to refer the case to the International Criminal Court in The Hague.
He has blamed the council's inability to act on Syria on the veto power held by several permanent members.
On Monday, Zeid blasted veto-wielding members for the council's intransigence on Syria and other conflicts, saying they bore "responsibility for the continuation of so much pain."
"It is time, for the love of mercy, that China, Russia and the United States... end the pernicious use of the veto," he told the rights council.