The Syrian Observatory for Human Rights said the Islamist fighters were killed during an offensive by loyalist forces backed by Hezbollah, aimed at seizing hills surrounding Yabrud, which is north of Damascus.
Regime aircraft launched six raids on the Al-Aqaba region on Friday, according to the Britain-based watchdog, which relies on reports from activists and medics on the ground.
The Yabrud offensive by Syrian ground forces bolstered by fighters from Lebanon's Shiite Hezbollah movement, an ally of President Bashar al-Assad, is aimed at severing a key rebel supply line linked to the town of Arsal in Lebanon's Bekaa Valley.