BEIRUT -- A car bomb targeting a checkpoint near a military airport in an upscale neighborhood of the Syrian capital killed 10 soldiers, activists said Monday as President Bashar Assad's troops pressed ahead with an offensive to regain territory they lost to rebels trying to topple his regime.
The army has scored major victories in key battlefields in western and central Syria in the past weeks, and is now setting its sights on the country's largest city, Aleppo, in the north, parts of which have been opposition strongholds.
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The Britain-based Syrian Observatory for Human Rights said 10 soldiers died in the Sunday night attack in Damascus' Mazzeh area and 10 were wounded. The neighborhood houses several embassies and a military airport.
Syrian state media confirmed there was a blast near the military airport late Sunday but did not release any casualty figures.
At least 93,000 people have been killed in Syria's conflict since it erupted in March 2011, according to a recent U.N. estimate.
Millions have been displaced and the civil war is increasingly being fought along sectarian lines, pitting Sunni Muslims against Shiites. It is also threatening the stability of Syria's neighbors, including Lebanon and Iraq.
Sunnis dominate the rebel ranks while the Assad regime is mostly made up of Alawites, an offshoot sect of Shiite Islam.
Sectarian divisions deepened in the conflict a few weeks ago, when Lebanon's Iran-backed Shiite militant group Hezbollah joined the fight inside Syria on the regime's side.
Earlier this month, Assad's troops dealt a major blow to the opposition forces after they pushed the rebels out of the strategic town of Qusair near the Lebanese border, largely with Hezbollah's help.
The fall of Qusair shifted the balance of power on the battlefield in favor of the Damascus regime, which is now looking to keep the momentum and aims to take back control of Aleppo, the country's commercial hub. The rebels captured parts of the city last summer during an offensive in the north along the border with Turkey.
While the rebels had been able to capture territory from the government in the past month, they have been unable to hold on and govern it effectively because of the regime's superior firepower.
Lack of services and aid flow into the rebel-held areas in the north have caused problems for the opposition and resulted in infighting between ethnic Kurdish and Arab groups fighting against Assad's regime in the predominantly Kurdish northern region of Afrin.
Arab rebels imposed a siege in late May on the area that resulted in a humanitarian crisis, according to the Observatory, which relies on a network of informants on the ground.
The region has a population of more than half a million, along with more than 200,000 internally displaced people, the Observatory said. Clashes between Kurdish gunmen and other rebel groups have been ongoing in the town of Afrin and surrounding villages for months, leading to a lack of food and medicine, and spikes in prices of basic goods.
The opposition has appealed to Western backers for weapons to be sent to them as soon as possible if they are to keep control of parts of Aleppo.
Troops clashed with rebels inside Aleppo and in the city's outskirts on Monday, the Observatory said. It also reported an airstrike on a village of Douweirina, a stronghold of an al-Qaida affiliated group fighting on the opposition's side.
President Barack Obama authorized lethal aid to the rebels for the first time last Friday, after Washington said it had conclusive evidence that the Syrian regime had used chemical weapons. Syria accused Obama of lying about the evidence, and says he resorted to fabrications to justify his decision to arm the rebels.
Russia, one of Assad's main allies, also criticized Obama decision.
Syria and the increasingly opposed positions of the U.S. and Russia over the civil war are expected to be high on the agenda of G-8 leaders meeting in Northern Ireland on Monday. Obama is expected to hold a bilateral meeting with Russian President Vladimir Putin.
In addition to arming the rebels, Washington has also been contemplating other options to support the opposition, including imposing a no-fly zone over Syria, though no decision has been made on measures that could ground Syrian military planes.
Assad's air force has been his most lethal weapon, one he's been relying on to prevent rebels from holding on to territory won on the ground.
A spokesman for Russia's Foreign Ministry, Alexander Lukashevich, said in a televised news conference Monday that "there are no conditions and no need for a no-fly zone" in Syria, adding that such measures by the U.S. and other would be "counterproductive."
The host of the G-8 meeting, British Prime Minister David Cameron conceded Monday there is a chasm on Syria, but said Russia, like all G-8 governments, has a responsibility to push opposing factions in the civil war to the negotiating table as rapidly as possible and not to back a government that "butchers" its citizens.
Russia supplies Assad's army with weapons and has its only Mediterranean port in Syria.
Cameron, who on Sunday met separately with Putin in London, said Russia and the West need to unite behind a diplomatic push that transitions Assad from power. Both leaders said they're hopeful Syria's warring factions can hammer out their differences at upcoming peace talks tentatively planned for next month in Switzerland.
In Geneva, Syria's ambassador to the United Nations said he was not optimistic about the prospects of holding a conference this summer.
Faysal Khabbaz Hamoui blamed the impasse on the armed opposition and told The Associated Press that the two sides remain too far apart to make it to the negotiating table in July.
However, there could still be some movement toward that goal depending on the outcome of talks among "major powers" at the G-8 Summit, Hamoui said.