Residents said air strikes hit two hospitals and a bakery in opposition-held eastern Aleppo on Wednesday.
At least six people were killed by artillery shelling in al-Maadi neighbourhood as they queued for bread at the bakery, residents and the Syrian Observatory for Human Rights said.
Hospitals under attack
According to AFP, two patients died at the M10 hospital.
“We are still trying to figure out if it was directly because of the attack or because treatment was cut off," Adham Sahloul of the Syrian American Medical Society (SAMS) said.
— SAMS (@sams_usa) September 28, 2016
"The warplane flew over us and directly started dropping missiles on this hospital...at around 4am," Mohammad Abu Rajab, a radiologist at the M10 hospital, told Reuters. "The rubble fell in on the patients in the intensive care unit."
The strikes also hit the hospital's oxygen and power generators, and patients were transferred to another hospital in the area, medical workers at the M10 hospital said.
The other hospital to be hit was the M2.
M2 and M10 are the codenames used locally to hide the location of the health facilities.
A ceasefire brokered by the pro-opposition United States and pro-regime Russia ended catastrophically within a week.
The failure to maintain calm was followed by a major offensive by the Assad regime against the opposition-held east of Aleppo.
The assault launched to take back the city has been one of the fiercest in the 5-year-old conflict.
"Negotiations with the Americans were just a smokescreen in order to buy time and prepare for the next phase of military operations," said Thomas Pierret, a Syria expert at the University of Edinburgh.
"For the (regime) loyalists, diplomacy is the continuation of war by other means," Pierret said.
Only a small amount of humanitarian aid reached war-ravaged Aleppo with a UN aid convoy also being bombed during the ceasefire.
Heavy bombardment raised international concern over the plight of 250,000 residents in eastern Aleppo, where food and vital medical supplies are running short.
— Dr Joanne Liu (@JoanneLiu_MSF) September 28, 2016
The World Health Organization (WHO) and the Red Cross on Tuesday called for dozens of sick and wounded people to be evacuated safely for treatment.
WHO said less than 10 hospitals, with only 35 doctors to care for hundreds of thousands of people, remained in the area.
The civil war in Syria erupted in early 2011, when Bashar al-Assad unleashed a brutal clampdown on anti-regime protests. United Nations and Arab League Envoy to Syria say at least 400,000 has died during the five-year-old conflict.
Millions have fled their homes, with many living in makeshift camps inside Syria or its neighbouring countries Turkey, Jordan and Lebanon. Refugees have predominantly been reliant on UN agencies funded by major UN members.