"In the opposition-controlled part of Aleppo over the past few days, pro-Government aircraft have destroyed a key hospital and other medical facilities reportedly killing a number of medical personnel, including the only remaining pediatrician in the area, as well as many patients.
In the Government-controlled part of Aleppo, another hospital was struck and many civilians killed in attacks launched in a number of neighbourhoods," the United Nations High Commissioner for Human Rights Zeid Ra’ad al-Hussein said in a statement.
"The violence is soaring back to the levels we saw prior to the cessation of hostilities. There are deeply disturbing reports of military buildups indicating preparations for a lethal escalation," he said.
"In the context of such an abysmal situation, the persistent failure of the Security Council to refer the situation in Syria to the International Criminal Court is an example of the most shameful form of realpolitik," he said.
"The cessation of hostilities and the Geneva talks were the only game in town, and if they are abandoned now, I dread to think how much more horror we will see in Syria," he added.
The UN envoy on Syria on Thursday appealed for a U.S. and Russian initiative "at the highest level" to end the Syria crisis, saying the truce was "in great danger" and "could collapse any time" as continued violence was "killing one Syrian every 25 minutes".
Germany accuses Assad regime of violating cease-fire
Germany also strongly condemned the airstrike that targeted Wednesday a field hospital in Aleppo and accused the Bashar al-Assad regime for undermining the cease-fire with continued attacks.
Chancellor Angela Merkel’s spokesman Steffen Seibert said Friday initial information has shown that, most likely, the regime was responsible for the attack that killed dozens at the hospital, which is financially supported by Germany.
"This attack does not only risks further escalation of fights around Aleppo but also threatens the cease-fire and the future of the hard-won Geneva process," Seibert said at a press conference in Berlin.
He called for an end to attacks that target civilians and hospitals, in violation of the cease-fire and international law.
"Systematic starvation and denial of medical assistance are methods of war that are especially used by the Syrian regime. This constitutes a blatant violation of international humanitarian law," he stressed.
Seibert also called on Russia to use its influence on Assad regime.
"We also see Russia, as the supporter the regime in Damascus, under obligation not to let the cease-fire and the political process collapse," he stressed.