UN Secretary General Ban Ki-moon condemned the Wednesday (September 28th) attacks on the two largest hospitals in opposition-held parts of Syria's Aleppo as "war crimes", AFP reported.

"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 UN Security Council.

Air raids hit the two largest hospitals in opposition-held parts of Aleppo early Wednesday, putting them temporarily out of service, the medical organisation that supports them said.

"The attack happened at 4 a.m. One warplane targeted both of them directly," said Adham Sahloul of the Syrian American Medical Society (SAMS).

"There are only six hospitals currently operational now that the M2 and M10 have been temporarily taken out of service," he said.

Both hospitals had intensive care units and trauma capacities and had been targeted in previous aerial attacks, according to Sahloul, who described the bombings as "deliberate".

At M10, the bigger of the two, the bombardment completely destroyed the facility's generator.

Three employees were injured at the second hospital, among them an ambulance driver, a nurse and an accountant.

"Two patients died. We are still trying to figure out if it was directly because of the attack or because treatment was cut off," Sahloul added.

Sahloul warned of devastating medical consequences if violence spiked again, as it did with heavy aerial strikes over the weekend, while the hospitals remain closed.