Over two dozen rebel fighters killed as government bombardment keeps closed only supply route into the northern city
Syrian rebels fought fierce battles with government forces in a failed bid to reopen their only supply route into Aleppo city overnight, losing at least 29 combatants, a monitor said on Sunday.
The assault sought to push government forces back from the Castello Road that leads into the opposition-held eastern half of Aleppo city, which is now effectively besieged by government troops.
The Syrian Observatory for Human Rights said 29 fighters from the Islamist Faylaq al-Sham rebel group and al-Qaeda affiliate Nusra Front were killed in fighting or by mines laid by government troops.
The Britain-based monitor said there were also deaths among government troops but had no immediate toll.
"The attack has ended and the road remains completely closed," said Observatory chief Rami Abdel Rahman.
The Castello Road was effectively severed by government forces on Thursday when they seized a hilltop within firing range of the key supply route.
By Saturday, government soldiers were within 500 metres of the road and firing on any vehicle attempting to use it.
An AFP correspondent in the eastern side of the city said opposition factions were preventing civilians from using the road.
Government artillery fire and barrel bomb attacks were reported to the east of the city on Sunday morning.
The violence came despite the army's announcement Saturday of a 72-hour extension to a nationwide ceasefire that began on Wednesday but has produced little respite in fighting.
The Observatory said at least one car had been targeted on the Castello Road early on Sunday morning, adding it was unclear if it was carrying civilians or fighters.
On Friday, a man and his two sons were killed by government forces while using the road, according to the monitor.
About 200,000 people remain in the eastern part of Aleppo, which has been divided between government and rebel control since shortly after fighting in the city erupted in mid-2012.
President Bashar al-Assad's forces have been trying to cut the Castello Road route for more than two years in a bid to pressure rebel forces in the city.
Their advance on Thursday has left residents of the east cut off, with supplies of basic items including food and fuel starting to run low and fears of a lengthy government siege.
Syria's government has been accused of using siege tactics to pressure rebel forces, and the UN says nearly 600,000 Syrians live in besieged areas, most surrounded by government forces, although rebels also use the method.
More than 280,000 people have been killed in Syria since the conflict began in March 2011 with anti-government protests.
The conflict has also seen large parts of the country fall under the control of the Islamic State (IS) group, which in 2014 declared a self-styled "caliphate" in territory under its control in Syria and Iraq.
A new analysis by the IHS research group said Sunday that IS had lost 12 percent of its territory in the two countries so far this year, after losing 14 percent in 2015.
The report said the territorial losses, as well as sinking revenues, would be likely to encourage IS to pursue "mass casualty attacks" in Iraq, Syria and further afield, including in Europe.