Hospitals in Aleppo are "all but obliterated," the United Nations warned Sunday, saying that bomb attacks had subjected civilians "to a level of savagery that no human should have to endure."
"Indiscriminate bombing and shelling continues in a shocking and unrelenting manner, killing and maiming" residents, U.N. Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator Stephen O'Brien said in a statement.
"We are in a race against time to protect and save civilians in eastern Aleppo city," he said. "They need our urgent action to bring an end to their living hell."
His plea came as Syrian government and allied forces advanced north of Aleppo, pressing their week-long offensive to take the insurgent-held part of the city after dozens of overnight air strikes hit the besieged eastern sector, state media and a monitor said Sunday.
The Syrian military, supported by Iran-backed militias and Russian air power, began their offensive to take control of the whole of the divided city of Aleppo after a week-long ceasefire broke down last month.
An initial air campaign by the Syrian government and its allied forces more than a week ago was later reinforced by a ground offensive seeking to establish control over the besieged insurgent-held eastern half of the city.
The Syrian Observatory for Human Rights and state television said the Syrian military and allies advanced south from the Handarat refugee camp north of Aleppo city, which they took earlier this week, into the Shuqaif industrial area.
Zakaria Malahifji, of the Aleppo-based rebel group Fastaqim, told Reuters there were clashes in this area on Sunday.
In his statement, O'Brien said that "indiscriminate bombing and shelling continues in a shocking and unrelenting manner, killing and maiming civilians, subjecting them to a level of savagery that no human should have to endure."
"The health care system in eastern Aleppo is all but obliterated," he added.
On Saturday, the largest trauma and intensive care center in eastern Aleppo was badly damaged by air strikes and had to close. Two patients were killed.
The Syrian American Medical Society (SAMS), which partly supported the hospital, said the hospital had been hit seven times since July, with three attacks this week alone.