The blast, which was likely caused by a booby-trapped car bomb, rocked the suburb of Ranskous near Damascus, Xinhua reported citing activists who did not give further details.
The Syrian government has not commented on the bombing.
The blast happened amid growing tension between moderate and radical rebels in several Syrian cities.
The Syrian opposition in exile said in a recent statement that the radical rebels were trying to "steal the revolution".
Meanwhile, in Geneva, the UNHRC Friday strongly condemned the continued gross, systematic and widespread violations of human rights and all violations of international humanitarian law in Syria and urged the government to grant immediate access to the UN commission of inquiry.
The UNHRC demanded that the Syrian authorities cooperate fully with the commission of inquiry, including by granting it immediate, full and unfettered access throughout the country, reported WAM, the official news agency of the United Arab Emirates.
"The council strongly condemned the continued gross, systematic and widespread violations of human rights and all violations of international humanitarian law by the Syrian authorities and affiliated militias, as well as any human rights abuses and violations of international humanitarian law by armed opposition groups," it said in a resolution adopted at the end of its 24th session.
In another development, Syrian President Bashar al-Assad said his government possessed non-chemical weapons that were so sophisticated they they could "blind" Israel anytime.
"During the 1980s, we manufactured chemical weapons as a deterrent to nuclear-armed Israel," AKI quoted Assad as telling Lebanese daily al-Akhbar Thursday.
"Now these are no longer a deterrent. Today, we have more important and sophisticated weapons capable of blinding Israel in an instant," he said.
The real objective of the US and its allies is not Syria's chemical weapons arsenal but to alter the regional balance of power and protect Israel, Assad added.
Assad said that Syria's decision to hand over its chemical weapons to the international community to be destroyed has caused Washington and other capitals "embarrassment".
"Now the ball is in their court," Assad said.
"We have thousands of tonnes of chemical weapons, which are a burden for us. Destroying them would cost us a huge amount of money and time," he added.
--IANS (Posted on 28-09-2013)