Syrian rebels captured an army base in the eastern oil province of Deir al-Zor on Thursday, striking another blow against President Bashar al-Assad's military and further weakening his 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, follows rebel takeovers of military installations in the north and center of the country this week.
Recent rebel momentum shows the increasing potency of the mainly Sunni Muslim fighters trying to topple Assad, from the Alawi minority linked to Shia 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 am (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 siege of 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." Another opposition source in contact with rebels confirmed that the base, 42 km (26 miles) southeast of the city of Deir al-Zor, had fallen.
Activists say 38,000 people have been killed in the 20-month-old 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 military campaign and wary of backing rebels who include Islamist militants, have stayed on the sidelines, although France and Britain formally recognized the opposition coalition this month.
Russia, which along with China has blocked three resolutions which could have led to UN sanctions against Assad, criticized 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 of Turkey's request for deployment to the Western military alliance.
The capture of the Mayadeen base leaves Assad controlling 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 the city to the border crossing of Albu Kamal.
Last week rebels seized a military airport 80 km southeast of Mayadeen, on the Iraqi border. Rebels also stormed a special forces base near Aleppo, Syria's commercial hub, and an air defense position in the southern suburbs of Damascus.
The Syrian Observatory for Human Rights, which monitors the violence through a network of activists, said Assad's forces pulled back on Thursday from three positions south of the town of Maarat al-Numan, on the highway linking Damascus to Aleppo.
Rebel fighters have been seeking to dislodge the army from a military base close to Maarat al-Numan. The town itself has been controlled by Assad's opponents for weeks.
Near Damascus, fighting continued around the south-western suburb of Daraya. Opposition campaigners said the army kept up heavy bombardment on the town where Free Syrian Army fighters appeared to remain 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.
Severe restrictions on non-state media make it impossible to verify opposition reports independently.
So far Assad's core military units, composed mainly of members of his Alawi 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 Damascus 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.