Three pro-Syrian regime fighters have been killed in an Israeli strike on a weapons' depot close to the Golan Heights, an official from the group told AFP.
The attack took place on al-Fawwar camp, near Quneitra, which saw two other fighters injured in the strike from either artillery or the air on Friday night.
A "weapons warehouse" at the camp was targeted in the attack, according to the Syrian Observatory for Human Rights.
Syrian state media said Israeli war planes hit a "military position" and came after regime forces attacked "terrorists" in the area.
Damascus refers to all opposition forces as "terrorists" and accused Israel again of supporting them.
Israel said on Friday said its forces "retaliated" after areas of the Golan Heights under its control came under mortar fire.
"The Israeli army targeted the source of the fire," it said.
Israel has occupied 1,200 square kilometres (460 square miles) of the Golan Heights since war with Syria and other Arab states in 1967.
Its annexation of the land is not recognised by the international community.
Israel has launched a number of air strikes on Hizballah targets and in "retaliation" when rocket or mortar fire hits areas it controls.
Agencies contributed to this story.