BEIRUT — In a multi-pronged offensive, Syrian government forces and their allies pushed into an area north of the city of Aleppo on Thursday, threatening a key supply line for the city's opposition-held quarters and setting off intense clashes with rebels, activists said.
The advance came despite of and in violation of the government's own cease-fire, which the authorities announced the day before to coincide with the Muslim holiday of Eid al-Fitr that marks the end of Ramadan.
Also Thursday, the international relief organization Mercy Corps warned its food stocks in the opposition-held half of the contested city of Aleppo could run out in a month. It said it provides food aid to 75,000 people there, among an estimated population of 300,000-400,000 in the rebel-held sections. The entire city, which is also the capital of Aleppo province, has about 2 million people.
"Unless we are able to resupply, it's going to be very difficult if not impossible to continue support beyond that," said Dominic Graham, who directs the organization's Syria efforts.
Fierce fighting also broke out in the eastern and southern suburbs of the Syrian capital, Damascus, activists and rebel fighters reported.
Islam Alloush, a spokesman for the Jaish al-Islam fighting group, said government forces moved in on the suburb of Mayda, seeking to block a rebel supply line, while the opposition fought back to regain a number of areas previously captured. Government advances were also reported in Daraya, a besieged opposition-held town overlooking Damascus airport, the opposition-operated Facebook account of the Local Council of Daraya reported.
On Wednesday, Syrian President Bashar Assad's government announced the 72-hour truce, ending on midnight Friday, an announcement welcomed by U.S. Secretary of State John Kerry and others. Kerry said efforts were underway to extend it.
On Thursday, Staffan de Mistura, the U.N. envoy for Syria, noted "initial reports of potential violations" but urged all parties to abide by the truce.
The rebel supply line to Aleppo is known as the Castello road and government forces and their allies, including Lebanon's Hezbollah militant group, have been mounting repeated attacks on it.
The government has so far secured control over the surrounding Mallah farms, leaving Syrian forces less than a mile (1.3 kilometers) away from Castello road, Hezbollah's media arm said, describing it as retaliation for violations of the truce by armed groups. Syrian State TV declared that, "terrorists are violating the truce."
Rebel Nour al-Din Zinky group said on its Facebook page that government warplanes and artillery shelled the Mallah farms close to the road. It said the rebels were trying to regain control of the farms.
The Britain-based Syrian Observatory for Human Rights, an activist group that tracks Syria's civil war, now in its sixth year, reported clashes west and east of Castello road.
Syria's state-run news agency said rebels shelled a government neighborhood of Aleppo on Wednesday, killing three people, while the anti-government Aleppo Media Center reported that at least two people were killed in government airstrikes and shelling on rebel-held neighborhoods of the contested city.
Mercy Corp's Graham said a previous, U.S.-Russia-brokered cease-fire, which started in February but eventually fell apart, had not helped the group's aid deliveries. The Islamic State group and Al-Qaida's Syria affiliate were excluded from that truce.
Ahmed Ramadan, an exiled Syrian political opposition member, wrote on his Twitter page that the Assad government's truce was a "hoax."
Associated Press Writer Sarah El Deeb in Beirut contributed to this report.