Earlier reports by a local TV broadcaster said that eight students and a teacher were killed in the attack on Bteiha School in the Wafideen camp, about 20 kilometers northeast of Damascus.
The Wafideen camp is home to some 25,000 people forced out of the Golan Heights, which has been occupied by Israel since 1967.
Although the attack was confirmed by the Syrian Observatory for Human Rights, the identity of the attackers remains unknown. Syria's state news agency reported that an unspecified group of rebels shelled the school.
"They were killed by a mortar launched by terrorists," the broadcaster said, referring to the rebels fighting the pro-government forces.
The suburbs of Damascus – a rebel stronghold since the uprising against President Assad began in March 2011 – have witnessed heavy fighting since last week after the army fought to regain lost territory around the capital.
The situation is Syria has deteriorated in recent days, prompting the UN to order "all non-essential international staff out of Syria" and halting aid missions outside Damascus.
The Syrian government claims that the conflict is being orchestrated from outside of the country.
Russian Deputy Foreign Minister Mikhail Bogdanov claimed that extensive supplies of weapons were being sent to the Syrian opposition, despite the arms embargo placed on the war-torn counthttp://rt.com/news/syria-students-killed-rebels-255/