The attack, which took place late Sunday in the Mazzeh district in western Damascus, comes as President Bashar Assad's forces press ahead with an offensive to regain territory they lost to the 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.
The Britain-based Syrian Observatory for Human Rights said Monday that 10 soldiers died in the attack in Mazzeh and 10 were wounded. The upscale neighborhood houses several embassies and a military airport. The Observatory, which relies on a network of informants inside Syria, did not state how many were deaths or how many were injuries.
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 battle for 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.
The opposition forces appealed to Western backers for weapons to be sent to them as soon as possible if they are to keep parts of Aleppo, where fighting raged on Monday, the Observatory said.
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 especially 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.
The host, British Prime Minister David Cameron, met separately with Putin on Sunday in London, where both said they're hopeful Syria's warring factions can hammer out their differences at upcoming peace talks tentatively planned for next month in Geneva.
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