The Syrian army is edging its way towards southeastern Aleppo as it battles rebel fighters for control of the northern city, a monitor and a pro-government daily said Tuesday.
The Syrian Observatory for Human Rights said it was a "limited advance" but the first by government troops in more than a year, and that residents fearing a major operation were fleeing the region.
The troops have gained some ground in Aleppo in the past few weeks, taking advantage of the fact that rebels who hold larges swathes of territory have turned their guns against jihadist fighters.
"The Syrian army made a limited advance, for the first time in more than a year, and seized the Karm al-Qasr district on the southeastern fringes of Aleppo," held by the rebels, said the Observatory.
The offensive was launched from Nairab military airport east of Aleppo, Syria's second city and pre-war commercial hub.
Al-Watan newspaper, which is close to President Bashar al-Assad's government, said the troops made the advance on Monday and also seized the districts of Ballura and Kasr al-Tarrab.
It too said the operation had been launched from Nairab airport in the east, as well as Aziza village in the south, while adding it had reached the outskirts of Mayssar, a rebel bastion in southeast Aleppo.
The Observatory said residents of Mayssar, nearby Marjeh and Inzarat were fleeing their homes for "neighbourhoods controlled by regime forces... because of the fighting".
Since December 15, Aleppo has been the target of an aerial offensive that has killed hundreds, mostly civilians.
On Tuesday at least three people were killed in regime air raids that targeted Qadi Askar and Mayssar, said the Observatory.
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On Saturday, Aleppo-based activist Mohammad Wissam said the army has taken advantage of the fact that rebels have recently turned their sights against jihadists.
"The army has deployed en masse around the east of the city, and families residing in the area have started to flee for other safer neighbourhoods and villages" fearing an all-out assault, he said.
Aleppo has been devastated by fighting between government and rebel forces that began in mid-2012.
Control of the city is now divided between the regime and rebels, while the opposition holds much of Aleppo province.
Meanwhile in Aleppo's northern countryside, rebels resumed battles against the jihadist Islamic State of Iraq and the Levant in Maaret al-Ratiq village, said the Observatory.
Fierce fighting has since January 3 pitted three massive rebel alliances against ISIL, killing more than 1,400 on both sides.
In recent weeks, ISIL has made suffered major losses in Aleppo and Idlib provinces, but re-consolidated itself in Raqa to the east.
While rebels initially welcomed jihadists in Syria, they turned against ISIL after its quest for hegemony and horrific abuses angered much of the opposition.
In Raqa city, ISIL on Monday detained a 16-year-old boy for not praying, and "lashed him 30 times," said the Observatory.
On another front, fighting between rebels and troops loyal to Assad in the south of the capital raged, killing eight opposition fighters and 15 soldiers, the monitoring group added.
Syria's war has killed more than 130,000 people and forced millions more to flee their homes.