Syria rebels urge Aleppo mobilisation to halt assault
A jihadist rebel group affiliated to al-Qaeda has joined calls for a mass mobilisation in the Syrian city of Aleppo to halt a government advance.
A statement by the Islamic State of Iraq and the Levant (ISIS) urged "all brigades and Muslims to face off against the enemy", activists said.
On Monday, six other Islamist rebel groups issued a call to arms in Aleppo.
It came after the army secured the area around the city's airport and retook a strategically important base nearby.
Analysts said the capture of Base 80, a large military position which rebels had held since February, would help troops move on opposition-held areas of Aleppo.
Earlier this month, they seized the town of Safira, south-east of the city. On Monday, the town of Tal Aran, on the Safira-Aleppo road, also fell.
In a separate development on Wednesday, government troops - backed by fighters from Lebanon's Hezbollah group - seized the southern Damascus suburb of Hujaira, Syrian state media said.
State TV showed soldiers walking on empty streets flanked by shelled buildings after days of fighting.
The Syrian Observatory for Human Rights reported that ISIS had published an urgent communiqué on Tuesday warning that the army had taken "part of the road linking Khanasser, Tal Aran and Safira because of the weakness of rebel groups".
ISIS acknowledged "many losses" from the fighting and called "all brigades and Muslims to arms to face off against the enemy which is attacking Islamic territory", the UK-based group quoted it as saying.
"Those with a valid excuse not to fight must supply weapons and money."
On Monday, six other rebel groups operating in Aleppo - including the al-Qaeda-affiliated al-Nusra Front, the hardline Islamist Ahrar al-Sham and the more moderate Liwa al-Tawhid - also urged people in the city to "face up to regime attacks".
Their joint statement said government forces backed by fighters from the Lebanese Shia Islamist movement Hezbollah, Iranian Revolutionary Guards and members of Abu al-Fadl Abbas, an Iraqi Shia militia, had launched a "fierce offensive to reoccupy" Aleppo.
Aleppo has been divided roughly in half by the government and opposition since mid-2012, when rebel fighters launched an offensive to gain control of northern Syria.
Opposition activist Mohammed Nour told Reuters news agency on Tuesday that some rebel-held districts of the city, including Hananu in the east, were looking vulnerable.
"Regime forces aided by Hezbollah, the Iraqis and the Iranians have launched a pincer movement from the north and the east and are closing in on major neighbourhoods," he said.
"Infighting has undermined Aleppo's defences," Mr Nour added, referring to clashes in the past two months between al-Qaeda affiliates and units aligned with the Western-backed Supreme Military Council.
The UN says more than 100,000 people have been killed since the uprising against President Bashar al-Assad began in 2011. More than 2.2 million Syrians have fled to neighbouring countries while an estimated 4.25 million have been displaced internally.