AMMAN/BEIRUT (Reuters) – Syrian rebels stormed a government-held area in northeastern Damascus on Tuesday for the second time in three days, sources on both sides said, pressing the boldest assault on the capital by opposition fighters in several years.

The spokesman for one of the main insurgent groups involved in the attack told Reuters the new offensive began at 5.00 a.m., targeting an area rebel fighters had seized from government control on Sunday before being forced to retreat.

A Syrian military source told Reuters rebel fighters had entered the area, setting off a car bomb at the start of the attack. The source said a group of rebels that had entered the area had been encircled and were “being dealt with”.

The rebel groups have launched the assault from their Eastern Ghouta stronghold to the east of the capital. Government forces have escalated military operations against Eastern Ghouta in recent weeks, seeking to tighten a siege on the area. The rebel assault aims partly to relieve that pressure.

The fighting has focused around the Abassiyin area of the northeastern Jobar district, some 2 km east of the Old City walls, at a major road junction leading into the capital.

A witness near the area heard explosions from around 5.00 a.m., followed by clashes and the sound of warplanes overhead.

Wael Alwan, the spokesman of rebel group Failaq al Rahman, told Reuters: “We launched the new offensive and we restored all the points we withdrew from on Monday. We have fire control over the Abassiyin garages and began storming it.”

The Syrian military source said: “They entered a narrow pocket – the same area of the (previous) breach – and now this group is being dealt with.”

BOMBARDMENT

The government says the attack is being carried out by fighters of the Nusra Front, a jihadist group that was al Qaeda’s official affiliate in the Syrian war until it declared they had broken off ties last year. The Nusra Front is now part of an Islamist alliance called Tahrir al-Sham.

The intensity of the Syrian army’s counterattack had forced the rebels to retreat from most of the areas they captured in the first attack.

The rebels have lost ground in the nearby areas of Qaboun and Barza.

A rebel commander said the Syrian army was intensifying its shelling on areas they had advanced in Jobar and towns across Eastern Ghouta.

“The bombardment is on all fronts … there is no place that has not been hit … the regime has burnt the area by planes and missiles,” said Abu Abdo a field commander from Failaq al Rahman brigade.

The Syrian government appears to be employing the same strategy it has used to force effective surrender deals on rebels elsewhere around the capital through escalated bombardment and siege tactics.

Rebel fighters have been granted safe passage to insurgent-held areas of northern Syria under such agreements.

The British-based Syrian Observatory for Human Rights, which monitors the conflict, said at least 143 air raids were conducted by the Syrian army on rebel held eastern parts of Damascus, mostly targeting Jobar, since the rebels launched their offensive.

President Bashar al-Assad and the Syrian army, along with allied Russian, Iranian and Shi’ite militia forces, have the upper hand in the war for western Syria, with a steady succession of military victories over the past 18 months.

For rebels, however, their first such large scale foray in over four years inside the capital has shown they are still able to wage offensive actions despite their string of defeats.

(Reporting by Suleiman al-Khalidi in Amman, Tom Perry in Beirut; Writing by Suleiman Al-Khalidi; Editing by Tom Perry and Alison Williams)