BEIRUT (AP) - Syria's military threatened a ground offensive in Aleppo and pounded the city's rebel-held neighborhoods with airstrikes on Friday, killing dozens, demolishing buildings and damaging a main water station in an escalation that could doom faltering attempts to revive a cease-fire.
Rebels vowed to fight to keep President Bashar Assad's forces out of their districts and shelled government neighborhoods, wounding several people, according to state media.
Diplomatic efforts in New York have failed to salvage a Syria cease-fire that lasted nearly a week, before giving way to what residents and activists say is a new level of violence. The bombing, which began in earnest late Wednesday, has been unprecedented, targeting residential areas, infrastructure and civil defense centers.
Aleppo, Syria's largest city and one-time commercial center, has been contested since July 2012, but in recent weeks, its eastern rebel-held neighborhoods have been under siege by government forces and their allies. During the cease-fire, aid convoys remained stuck on the Turkish border unable to reach rebel-held parts of the city where some 250,000 people live, even though aid delivery was part of the U.S.-Russia truce agreement.
The Britain-based Syrian Observatory for Human Rights said at least 27 civilians, including three children, were killed in dozens of raids that began overnight. A member of the city's forensic team, Mohammed Abu Jaafar, said he had documented 54 deaths since late Thursday, including many women and children.
A photograph circulating on social media showed the bodies of a woman and her two children who were killed in one of the airstrikes on Aleppo. The three were shown lying in bed, their bloodied bodies covered in dust and debris as a rescue worker crouched next to them. The woman held a bloodied infant; lying next to her was the body of a young boy, his blue shirt covered in blood.
The Observatory said dozens of people were wounded and an unknown number remained buried under the rubble of buildings destroyed in the airstrikes that began in the early hours Thursday. A young girl was pulled out alive from a collapsed building in the city's Bab al-Nairab neighborhood early Friday, according to Ibrahim Alhaj, a rescue worker with the Syrian Civil Defense, also known as the White Helmets.
A video posted online by several Syrian social media sites showed the girl's rescue. In other footage, a weeks-old infant girl was shown being pulled from under the rubble of an apartment building.
Dozens more civilians were killed in other parts of Aleppo province, including at least 15 in the village of Bushqateen, three in Kfar Hamra and 11 in Al-Bab, a stronghold of the Islamic State group, according to forensic team member Abu Jaafar and the Observatory.
The pressure on rebel-held parts of the city is the most serious in years now that all areas are surrounded by government forces and their allies, including Iraqi fighters and militants from Lebanon's Hezbollah group.
Civil defense centers were being targeted in the bombing campaign, rescue worker Alhaj said. By Friday morning, one center in the rebel-held Ansari neighborhood in the southern part of city had been put out of service. Ambulances and the lone fire engine that serves the rebel-held districts were damaged.
In another center, a bomb fell in the courtyard, although there were no reported casualties among the group's volunteers.
"It is really critical. (Assad's air forces) have directly targeted civil defense centers," Alhaj said. "I have not seen in my life such bombardment. It is very, very intense."
A Syrian military official said Friday that airstrikes and shelling in Aleppo would continue for an extended period and the operation would expand into a ground invasion of rebel-held districts. The unnamed military official was quoted by Syrian state media as saying that operations in rebel-held eastern parts of the city "will include a ground offensive."
The military said leaflets were dropped over rebel-held parts of the city calling on opposition gunmen to surrender and take advantage of a recent amnesty issued by the state for fighters who agree to put down their arms. "The belt is getting tighter around you. Surrender now or you will meet your inevitable destiny," read one leaflet, which had a photo of the body of a bearded militant with a rocket-propelled grenade next to him.