AMMAN (Reuters) - Syrian rebels captured an army base in an eastern oil province on Thursday, further weakening President Bashar al-Assad's control in the strategic region bordering Iraq.
The capture of the artillery base on the outskirts of Mayadeen, a town on the Euphrates river near some of Syria's main oilfields, followed rebel takeovers of military installations in the north and centre of the country this week.
Recent rebel momentum shows the increasing potency of the mainly Sunni Muslim fighters trying to topple Assad, who belongs to the Alawite minority linked to Shi'ite Islam. But insurgents have often had to retreat quickly after making advances to avoid strikes by the president's air force.
"The Mayadeen military base fell at 8.30 a.m. (0630 GMT)," Abu Laila, an official in the Military Revolutionary Council in the province, told Reuters. He said 44 rebel fighters had been killed in the operation to capture the base.
"The whole countryside, from the Iraqi border and along the Euphrates to the city of Deir al-Zor, is now under rebel control," he said.
Another opposition source in contact with rebels confirmed the base, 42 km (26 miles) south-east of Deir al-Zor, had fallen.
Video posted online showed rebels on motorcycles and trucks apparently inside the base waving victory signs as smoke rose from two buildings. Artillery pieces could be seen on the ground and a tank transporter stood abandoned.
Severe restrictions on non-state media make it impossible to verify opposition reports independently.
Activists say 38,000 people have been killed in the 20-month uprising which threatens to draw in regional Sunni and Shi'ite Muslim powers. Hundreds of thousands have fled the country and 2.5 million are displaced, aid groups say.
Western states, anxious to avoid another costly Middle East conflict and wary of backing rebels who include Islamist militants, have stayed on the sidelines, although France and Britain formally recognized a newly formed opposition coalition as the sole representative of the Syrians this month.
Russia, which along with China has blocked three resolutions which could have led to U.N. sanctions against Assad, criticized on Thursday proposals for NATO to deploy Patriot missiles in Turkey near the Syrian border.
"This would not foster stability in the region," Foreign Ministry spokesman Alexander Lukashevich said.
The capture of the Mayadeen base leaves Assad in control of just three major army bases in Deir al-Zor province, said Sheikh Nawaf al-Bashir, a local tribal leader. He said rebels now held the main road to Iraq, from the outskirts of Deir al-Zor city to the border crossing of Albu Kamal.
The rebel move follows the capture last week of a military airport on the Iraqi border southeast of Mayadeen. In the last five days rebels have also stormed a special forces base near Aleppo, Syria's commercial hub, and an air defense position in the southern suburbs of Damascus.
In another setback for Assad, his forces pulled back on Thursday from three positions south of the town of Maarat al-Numan, on the highway linking Damascus to Aleppo, according to the opposition Syrian Observatory for Human Rights.
The area has seen heavy fighting between rebel forces, which have held the town for several weeks, and soldiers camped in a nearby military base, just 500 meters from the highway.
Near Damascus, opposition campaigners said fighting continued around the south-western suburb of Daraya and the army kept up heavy bombardment of the town, where Free Syrian Army fighters appeared to be entrenched.
To the east, clashes were also reported in the Damascus neighborhood of Jobar, which is adjacent to the main Abbasid Square. A mother, her daughter and her sister's husband were killed in shelling aimed at pushing back rebels, activists said.
Rebels in the south Damascus district of Hajar al-Aswad showed video of a captured air defense officer they identified as Colonel Bashir al-Saleh, flanked by two masked rebels carrying AK47s.
So far Assad's core military units, composed mainly of members of his Alawite minority sect, have prevented a sustained rebel push into the heart of the capital itself. The rebels have yet to hold a major Syrian city.
But activists say the rebels are gaining strength in Damascus, partly because they are being joined by fighters from outlying regions. While Assad's forces control main road junctions there have been guerrilla attacks in the last few days near Damascus Airport and rebels have expanded control of the mixed urban and farmland regions around the capital.
The Observatory said army shells struck a building next to Aleppo's Dar al-Shifaa hospital on Wednesday, one of the main rebel medical centers, killing 15 people. Most of the dead were fighters but a doctor and three children also died, it said.
Writing by Dominic Evans; Editing by Andrew Heavens and Robin Pomeroy