A fresh wave of intense air strikes battered Aleppo's opposition-controlled east, said an AFP correspondent in the city facing its worst violence in years. During an emergency session of the UN Security Council, US ambassador Samantha Power accused Russia of "barbarism", while the British and French envoys went even further.
"War crimes are being committed here in Aleppo," Francois Delattre of France said, while Britain's envoy spoke of bunker-busting bombs and more sophisticated weaponry unleashing a "new hell" on Syrians.
"It is difficult to deny that Russia is partnering with the Syrian regime to carry out war crimes," said Britain's Matthew Rycroft. The Kremlin hit back. Spokesman Dmitry Peskov denounced "the overall unacceptable tone and rhetoric of the representatives of the United Kingdom and the United States, which can damage and harm our relations".
Despite the exchange, the violence showed no signs of abating on the ground, with people in Aleppo saying food and vital medical supplies were dwindling to nothing. The Syrian Observatory for Human Rights monitor said the latest raids killed four civilians in the districts of Al-Mashhad and Sukari.
The Observatory said at least 132 people, nearly all civilians, had been killed in Syrian and Russian raids on eastern Aleppo since late Thursday. Among them were 20 children and nine women, Observatory director Rami Abdel Rahman said.
It was the fourth day of intense bombardment since a defiant Syrian regime launched a new assault to retake all of Aleppo following the collapse early last week of a short-lived ceasefire brokered by Moscow and Washington.
A Syrian military source told AFP regime forces had no intention of letting up on rebel-held areas. "The air force will bomb any terrorist movements, this is an irreversible decision," the source said, reiterating that the regime's goal was to "recapture all regions of Syria" outside its control.
A medical source in rebel-held Aleppo said hospitals were struggling to deal with a huge number of casualties.