Syrian rebels have recaptured key towns in the northern Aleppo countryside after intense battles with government forces, rebels and activists have told Al Jazeera.

Al-Qaeda-affiliated group Jabhat al-Nusra said on Saturday they had recaptured Hardatnin town in the northern Aleppo countryside after five days of fighting with government forces. 

The group said government forces had been supported by Hezbollah and Iranian fighters. 

Meanwhile, the UK-based Syrian Observatory for Human Rights (SOHR), said government forces had withdrawn to the town of Bashakuy further south in Aleppo province. 

At least 248 combatants, including 129 government soldiers and 119 rebel fighters have been killed since the fighting started on Tuesday, according to SOHR.

The fighting started when government forces launched a sudden offensive and captured three rebel held towns of Rityan-Hardatnin-Bashkuy that hold a strategic position and cut rebel final route to the city.

'Freeze hostilities' 

Earlier on Saturday, SOHR said government forces had also bombarded places in the town of Hayyan, leaving several people wounded, some of them in critical condition.

Meanwhile, UN Secretary General Ban Ki-moon has called for an immediate de-escalation of the conflict in Syria to give civilians some relief and allow a step towards a political solution to the four-year conflict, a spokesman for the UN chief said on Friday.

Stephane Dujarric said Ban is calling on all rival parties in Syria to freeze hostilities in the largest city of Aleppo to make way for the UN to experiment with delivering humanitarian aid to a densely-populated and contested area in the city.

"The Secretary General appeals all parties to de-escalate the conflict in order to provide a reprieve for the long-suffering civilians of Syria.

An immediate de-escalation is a much needed step towards a political solution to the conflict," he said at a news briefing at the UN headquarters on Friday.

The UN chief also urges the Syrian government to honor its commitment of a six-week suspension of airstrikes and artillery shelling in Aleppo, as proposed by the UN special envoy to Syria Staffan de Mistura, said Dujarric. 

The overall conflict in Syria has killed at least 220,000 people and sent more than 3.8 million people fleeing the country.

Source: Al Jazeera