Syrian regime forces were on the defensive around Aleppo on Sunday after a rebel alliance said it inflicted a major setback by breaking a three-week government siege of the battered city.
A coalition of rebels and jihadists surged through regime territory on Saturday to open a new route into Aleppo's besieged eastern neighbourhoods, home to an estimated 250,000 people.
The breakthrough was met with euphoric scenes among civilians and opposition fighters in eastern districts, but sparked fear of food shortages among residents of regime-controlled western areas.
Rami Abdel Rahman, head of the Syrian Observatory for Human Rights, said the development was one of the most significant setbacks for government forces since the conflict erupted in March 2011.
"Despite more than 600 Russian strikes, the regime forces were not able to hold on to their positions," he said.
Steadfast regime ally Moscow has provided air support for forces loyal to President Bashar al-Assad since September 2015.
State media denied that the siege had been broken and that its own forces were surrounded, saying the battle for Syria's second city was ongoing.
"The terrorist groups are suffering huge losses and were not able to break the encirclement of the eastern neighbourhoods of Aleppo," state news agency SANA said late Saturday, quoting a military source.
State television on Sunday said: "Our forces have redeployed after absorbing the attack of thousands of mercenaries, and the army has found a new route to allow food and gas in."
The Observatory said there were intermittent air strikes and clashes on the southern edges of the city on Sunday, where the opposition alliance overran a series of buildings in a military academy the previous evening.
They then pushed northeast into the district of Ramussa, linking up with rebel groups that had fought south from inside the city.
Rebels posted footage of their fighters embracing and celebrating the end of the government encirclement, in place since July 17.
On Sunday, rebel forces brought seven pick-up trucks full of fruit and vegetables into the eastern districts of Aleppo to be distributed to local markets, an opposition fighter said.
Video footage seen by AFP showed crates of plums, tomatoes, watermelons and other greens lined up along a road.
An AFP journalist said the goods were very quickly purchased by hungry residents in the eastern districts.
But the route remains open only to military movements, and "not a single civilian has left the eastern districts because the road is too dangerous and not secured," Abdel Rahman said.
The rebel advance now puts the estimated 1.2 million living in government-held districts of the city under opposition encirclement, he added.
"The western districts of Aleppo are now besieged. There are no safe routes for civilians in government-held districts to use to get into or out of the city," he told AFP.
Families in the western districts late Saturday rushed to buy any food and drink left in preparation for shortages.
"Unfortunately, after the road was cut, the price of a loaf of bread immediately shot up from 200 to 800 Syrian pounds," said Walaa Hariri, a mother of three.
"I sent my sons to school but they are all nervous, and the teachers replaced their regular lessons with courses on what to do if there is shelling," said the 48-year-old resident of the regime-held Furqan district.
Another 34-year-old resident told AFP that he has "faith in the army, but I can't help being scared."
"Food is already getting more expensive and the coming days risk being very difficult," he said.
The fight for Aleppo is among the fiercest so far in Syria's chaotic multi-front war, which has killed more than 280,000 people.
Rebel and regime forces have fought to control the provincial capital since mid-2012, transforming the former economic powerhouse into a divided, bombed-out city.
SANA said 10 civilians were killed on Saturday in rebel shelling on two government-held districts.
On Sunday, at least one girl was killed in opposition fire on Hamdaniyeh, said the Observatory.
The Britain-based monitor said at least 130 civilians have been killed since the opposition alliance launched its offensive on southern Aleppo on July 31.
More than 700 fighters from both sides had been killed in the onslaught, most of them rebels because of the regime's "aerial superiority," it said.
Syria's former Al-Qaeda affiliate said it had seized huge caches of weapons from regime forces in the artillery school south of Aleppo.
The Fateh al-Sham Front posted photos apparently showing artillery, trucks, armoured vehicles, and other weapons in wooden crates.
Syria's conflict erupted in March 2011 with protests against Assad's rule but has since evolved into a brutal war that has drawn in world powers.