DAMASCUS — Syrian government forces took a step towards completely encircling rebel-held parts of Aleppo on Thursday, capturing ground overlooking the only road into the opposition half of the city and effectively putting those areas under siege.

The army’s advance towards the Castello Road, which brought it to within its firing range, came during a 72-hour ceasefire announced by the Syrian army on Wednesday, which a monitoring group said had been a ruse.

Rebels said they were fighting to retake lost positions and re-secure the road. Its capture brings the Syrian government closer to its long-standing objective of encircling rebel-held areas of the northern city.

Aleppo, which was Syria’s largest city before the civil war with a population of more than two million people, has been divided for years into rebel and government sectors.

Heavy aerial and artillery bombardment had at times made the Castello Road impassable. But Thursday’s advance brings government forces the closest so far to the road, making it even easier to hit and effectively cutting off the opposition-held sector of the city near the Turkish border.

“Currently, nobody can get in or out of Aleppo,” Zakaria Malahifji of the Aleppo-based rebel group Fastaqim told Reuters.

He said government-allied forces were being aided by Iranian fighters and that reinforcements on the government side had arrived from further south.

The Syrian Observatory for Human Rights said the advance by pro-government
forces in the al-Malah Farms area had brought them to within less than a mile of the road.

The army said what it described as terrorist groups had tried to attack army positions in the area and that it thwarted this assault and taken over the southern al-Malah farms, coming to within firing distance of the Castello Road.

Pro-Damascus TV channels showed footage of tanks and troops firing and of the areas captured, which consisted of flat farmland and a number of buildings reduced to rubble.