UN Secretary-General Ban Ki-moon condemned the attacks Wednesday on the two largest hospitals in rebel-held parts of Syria's Aleppo as "war crimes."
"Let us be clear. Those using ever more destructive weapons know exactly what they are doing. They know they are committing war crimes," Ban told the Security Council.
"Imagine the destruction. People with limbs blown off. Children in terrible pain with no relief," he said. "Imagine a slaughterhouse. This is worse."
The two biggest hospitals in rebel-controlled parts of Aleppo have been bombed in what non-government organizations residents say are deliberate attacks by the Syrian regime and its Russian allies to eliminate these structures.
In May, the UN Security Council adopted a resolution on the protection of health workers and facilities during armed conflicts, but there has been no letup in these kinds of attacks in Syria and Yemen.
"International law is clear: medical workers, facilities and transport must be protected. The wounded and sick -- civilians and fighters alike -- must be spared," Ban said.
"Deliberate attacks on hospitals are war crimes. Denying people access to essential health care violates international humanitarian law."
Ban cited statistics gathered by Physicians for Human Rights that show that 95 percent of the medical personnel who were in Aleppo before the war "have fled, been detained, or killed."
"There must be action. There must be accountability," he said.