The Syrian Observatory for Human Rights said several groups, including the jihadist Al-Nusra Front, were behind the capture of the depot of anti-tank weapons and rockets.
"Liwa al-Islam, Al-Nusra Front, Al-Tawhid battalion, the Maghaweer (rebel commando force) and the Qalamun Martyrs' battalion... Captured an ammunitions depot near the village of Qaldun in the Qalamun area" northeast of the capital, the Britain-based Observatory said.
They seized "anti-tank weapons and ground-to-ground Grad missiles, as well as a variety of other ammunition, after clashes overnight from Friday to Saturday", it said.
Elsewhere, the army shelled rebel-held areas of the central city of Homs, focusing on the neighbourhoods of Juret al-Shiyah and Qussur, said the Observatory.
After the rebels lost the Khaldiyeh district this week, the army has pushed on with its bid to dislodge them completely from Syria's third city.
In the northern province of Hasakeh, jihadists and Kurds clashed two weeks after the expulsion of radical Islamists from the strategic Kurdish town of Ras al-Ain, opening up a new front in Syria's raging war.
Yesterday alone, at least 110 people were killed across Syria, the Observatory said.
