Satellite images released by Israeli intelligence firm ImageSat Intl (ISI) on Sunday show the complete deployment of all four Russian-made S-300 missile defense systems in Syria’s Masyaf province.In February, satellite images released by the Israeli satellite company showed three out of the four systems had been erected with one launcher observed covered by a camouflage net.The camouflaging of the fourth launcher “is rare and raises question marks about the operational level of the whole battery and specifically of the covered and folded launcher,” ISI said at the time.Russia delivered the launcher, radar and command-and-control vehicle of the advanced air-to-surface missile system to the regime of Syrian President Bashar Assad in early October as a response to the downing of a Russian reconnaissance plane by Syrian air defenses during an Israeli airstrike on Iranian targets the previous month.Moscow said it would also impose electronic countermeasures over Syria’s coastline to suppress satellite navigation, onboard radar systems and communications of warplanes attacking targets on Syrian territory.The incident led to one of the lowest points in the relationship between Jerusalem and Moscow in years.With the help of the Russians, Iranians and Hezbollah, Assad has regained control over the majority of Syria and is rebuilding his army, focusing first on intelligence and air defense divisions which could pose a threat to Israeli aircraft.Israel has been carrying out airstrikes in the war-torn country against Hezbollah and Iranian targets and has stressed that it will continue to operate when necessary.In April, an airstrike blamed on Israel completely destroyed a possible Iranian surface-to-surface missile factory in Syria’s Masyaf. The possible surface-to-surface missile factory included a main hangar measuring 60x25 meters and several big industrial hangars and buildings which probably serve for production and assembly of missiles.“The main industrial structures were completely destroyed, including the main hangar and the adjacent three production hangers and buildings; the rest of the structures were affected and damaged by the blast,” ISI said in an assessment at the time, adding that they “assess that all the elements and/or equipment which were inside are completely destroyed as well.”“However, there is probably no manufacture nor assembly of missile engines and warheads in this factory, since protected structures weren’t detected. Also no missiles or launchers were identified within the compound,” ISI said.Israeli officials have repeatedly voiced concerns over Iran’s entrenchment in Syria and the smuggling of sophisticated weaponry to Hezbollah from Tehran to Lebanon via Syria, stressing that both are redlines for the Jewish state.Syrian air defenses are largely antiquated Soviet-era systems, with SA-2s, SA-5s, and SA-6s as well as the more sophisticated tactical surface-to-air missiles such as the SA-17s and SA-22 systems. Moscow has also supplied the short range Pantsir S-1 to the Assad regime.The advanced S-300 would be a major upgrade to the Syrian air defenses and would pose a threat to Israeli jets on missions as the long-range missile defense system can track objects such as aircraft and ballistic missiles over a range of 300 km.A full battalion includes six launcher vehicles with each vehicle carrying four missile containers for a total of 24 missiles, as well as command-and-control and long-range radar detection vehicles.The system’s engagement radar, which can guide up to 12 missiles simultaneously, helps guide the missiles towards the target. With two missiles per target, each launcher vehicle can engage up to six targets at once.