Russian or Syrian warplanes knocked two hospitals out of service in the besieged rebel sector of Aleppo on Wednesday and ground forces intensified an assault in a battle which the United Nations said had made the city worse than a slaughterhouse, Reuters reports.
Two patients died in one of the hospitals and other shelling killed six residents queuing for bread under a siege that has trapped 250,000 people with food running out.
Only about 30 doctors are believed to be left inside the besieged zone, coping with hundreds of wounded a day.
"The warplane flew over us and directly started dropping its missiles ... at around 4 a.m.," Mohammad Abu Rajab, a radiologist at the M10 hospital, the largest trauma hospital in the city's rebel-held sector, told Reuters.
"Rubble fell in on the patients in the intensive care unit."
M10 hospital workers said oxygen and power generators were destroyed and patients were transferred to another hospital.
There were no initial reports of casualties there, but medical charity Médecins Sans Frontières (MSF) said two patients had been killed at the other hospital, in shelling which took it out of service as well, leaving east Aleppo with only seven doctors in a position to undertake surgery.
The government of President Bashar al-Assad, backed by Russian air power, Iranian ground forces and Shi'ite militia fighters from Iran, Iraq and Lebanon, has launched a massive assault to crush the rebels' last major urban stronghold.
Syria's largest city before the war, Aleppo has been divided for years between government and rebel zones, and would be the biggest strategic prize of the war for Assad and his allies.
Taking full control of the city would restore near full government rule over the most important cities of western Syria, where nearly all of the population lived before the start of a conflict that has since made half of Syrians homeless, caused a refugee crisis and contributed to the rise of Islamic State.