Syria's regime and rebels were locked in fierce fighting Sunday on Aleppo's western edges, where 41 civilians have been killed in an opposition offensive to break a devastating government siege. Rebels have unleashed car bombs and salvos of rockets and shells to break through government lines and reach the 250,000 people living in the city's east.
Syrian state media on Sunday accused them of firing shells containing toxic gas into government-controlled districts. State news agency SANA reported that 35 people were suffering from shortness of breath, numbness, and muscle spasms after "toxic gases" hit the frontline district of Dahiyet al-Assad and regime-held Hamdaniyeh.
The head of Aleppo University Hospital, Ibrahim Hadid, told state television that "36 people, including civilians and combatants, were wounded after inhaling toxic chlorine gas released by terrorists".
Syria's second city, Aleppo has been ravaged by some of the heaviest fighting of the country's five-year war which has killed more than 300,000 people. Intense fighting on Sunday rocked western districts, battered by hundreds of rebel rockets and artillery fire, according to Rami Abdel Rahman, head of the Syrian Observatory for Human Rights.
Two days of heavy rebel bombardment have killed 41 civilians, including 16 children, and wounded 250, according to the Britain-based Observatory.
In a new toll Sunday, it said fighting had also killed 55 regime and allied fighters, as well as 64 Syrian rebels.
The civilian toll was slammed by UN peace envoy to Syria Staffan de Mistura, whose office said he was "appalled and shocked by the high number of rockets" fired by rebels. "Those who argue that this is meant to relieve the siege of eastern Aleppo should be reminded that nothing justifies the use of disproportionate and indiscriminate weapons, including heavy ones, on civilian areas and it could amount to war crimes," his office said in a statement.
Fighting lasted all night and into Sunday, with air strikes and artillery fire along the western battlefronts heard even in the eastern districts, an AFP correspondent there said.
Plumes of smoke could be seen rising from the city.
About 1,500 rebels have massed on a 15-kilometre (10-mile) front along the western edges of Aleppo since Friday, scoring quick gains in the Dahiyet al-Assad district but struggling to push east since then. "The advance will be from Dahiyet al-Assad towards Hamdaniyeh," said Yasser al-Youssef of the Noureddin al-Zinki rebel faction.
Hamdaniyeh is a regime-held district directly adjacent to opposition-controlled eastern neighbourhoods. An AFP correspondent saw about a dozen civilians, including women and children, fleeing Dahiyet al-Assad on Sunday. They brought belongings stuffed into plastic bags, hoisting them on top of their heads or dragging them along the dusty road.
A pro-regime military source told AFP that the rebel assault was "massive and co-ordinated" but insisted it was unable to break into any neighbourhoods beyond Dahiyet al-Assad.
"They're using Grad missiles and car bombs and are supported by foreign fighters in their ranks," he said.
Those engaged in the assault include Aleppo rebels and reinforcements from Idlib province to the west, among them the jihadist Fateh al-Sham Front, which changed its name from Al-Nusra Front after breaking ties with Al-Qaeda.
Aleppo's front line runs through the heart of the city, dividing rebels in the east from government forces in the west.
Much of the once-bustling economic hub has been reduced to rubble by artillery and air bombardment, including barrel bombs - crude unguided explosive devices that also kill indiscriminately.