AMMAN (Reuters) - Syrian army and Shi'ite Muslim fighters attacked Sunni rebel areas in southern Damascus on Sunday in an offensive aimed at breaking resistance to President Bashar al-Assad around the capital, activists said.
Militia from Iran and Iraq and the Lebanese Shi'ite group Hezbollah, who overran two southern suburbs last month, are looking to build up their advances by capturing opposition districts closer to the centre of Damascus, the sources said.
Fighters from the al-Qaeda linked al-Nusra Front and the Islamic State for Iraq and the Levant, which is heavily comprised of foreign jihadists, have joined Islamist rebel brigades and Free Syrian Army units in close quarters fighting around the district of Hajar al-Aswad.
Hajar al-Aswad is mainly inhabited by refugees from the Israeli occupied Golan Heights. It is one of a series of Sunni districts on the edge of Damascus at the forefront of the uprising against Assad, who belongs to the Alawite sect, an offshoot of Shi'ite Islam that has dominated Syria since the 1960s.
Rami Al-Sayyed, an activist in Hajar al-Aswad, said the bombardment was the heaviest since the uprising erupted in March 2011.
"We are being hit with mortars, tanks, artillery, and rockets. Civilians trying to find a way to flee are not spared. Over the last few days field hospitals took more than 150 wounded, mainly civilians," he said.
Activists said aerial, artillery and rocket barrages on Hajar al-Aswad had killed at least 30 civilians in the last three days. Ten rebels were also killed.
No firm casualty figure was available for their opponents but opposition sources said up to 30 foreign Shi'ite fighters were killed and wounded in an ambush by al-Qaeda linked Islamists last week.
Heavy fighting was reported in the adjacent neighbourhood of Sbeineh, situated on the southern highway between Damascus and Deraa, and in the nearby district of Hajeera.
"People continue falling...in Hajar al-Aswad as heavy regime bombardment enters its fourth day. Artillery fire on the besieged district has not stopped," a statement by the Syrian Revolution General Commission said.
The statement said a four-year old also died on Sunday from malnutrition brought about by the siege, which has already caused several deaths among children. The deaths could not be independently confirmed.
There was no immediate comment from Syrian authorities. Official media previously said that Assad's forces were fighting al-Qaeda "terrorists" in the area.
A Middle East based diplomat following the fighting said Assad's forces were trying "to bite off slowly" section after section of Hajar al-Aswad and surrounding districts.
"The victims of this kind of warfare are mainly civilians. The militia masses to take a specific area after it has been basically wiped out by bombardment. They rest and then move to the next area," he said.
Video footage activists said were found in mobiles of dead Shi'ite fighters from the Iraqi Abu Fadl al-Abbas unit purportedly showed militiamen with Iraqi accent firing mortar bombs and heavy machine guns in southern Damascus while reciting Shi'ite slogans.
Other footage showed an Iraqi fighter distributing sweets to his comrades in the captured Sunni suburb of Thiabiya during the Eid al-Adha feast last month. The footage could not be independently verified.
The 2-1/2-year-old war has killed more than 100,000 people and forced millions from their homes into refugee camps in neighbouring countries.
(Editing by Ralph Boulton)