Britain-based war monitoring group the Syrian Observatory for Human Rights, along with the National Defense Forces (NDF) militia in southern Syria reported that a military base in Quneitra province was attacked on Sunday.
It remained unclear whether the bombardment came from an air strike or shelling, the British watchdog said, adding that it had struck a "weapons warehouse" in the camp.
Three members of the pro-government NDF were reportedly killed while two were wounded; an unnamed militia official was quoted as saying by news agency AFP.
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The Israeli army did not immediately comment on Sunday after the attack. On Friday it said it had struck positions inside Syria in response to mortar fire near the border.
Israel captured part of the Golan Heights from Syria in the 1967 Six Day War and later annexed it in a move which was never recognized by the international community. Technically, Syria and Israel are still at war, but the disputed area remained more or less quiet for decades.
There have been several instances of cross-border fire in the six years of the Syrian conflict but Israel has largely refrained from intervening; launching only occasional strikes mainly targeting Hezbollah forces.
se/rc (AFP, AP, Reuters)