Israeli officials believe that the S-300 anti-aircraft missile system which Russia delivered to Syria is not yet operational.
This follows the publication of pictures recently taken by an Israeli satellite showing how the system has been deployed in northwestern Syria.
According to the report provided by ISI, the system was deployed near an S-400 air defense system operated by the Russian army, which does not allow the Syrians to use it.
The photographs also show that the site has been operating 24 hours a day in recent weeks in order to implement the system. According to the report, there are at least four batteries deployed there, but they are not yet operational.
At the same time, it appears that various elements have been placed in the area in order to disguise the activity being carried out there.
Russia had previously provided the S-300 system to Iran.