Russian S-300 missile system
Russian S-300 missile systemiStock

Russia’s recent supply of S-300 air-to-missile systems to Syria was free of charge, a Russian military diplomatic source told the TASS news agency on Monday.

"On October 1, three battalion sets of S-300PM systems of eight launchers each were delivered to Syria," the source said.

"These systems were previously deployed at one of the Russian aerospace forces’ regiments which now uses the S-400 Triumf systems. The S-300 systems underwent capital repairs at Russian defense enterprises, are in good condition and are capable of performing combat tasks," the source added.

According to the source, along with the launchers Russia delivered more than 100 surface-to-air guided missiles for each battalion.

Russian Defense Minister Sergei Shoigu said last week that the delivery of the system to Syria had been completed and that work on preparation and training of the crews will be completed by October 20.

The missile system, originally developed by the Soviet military, but since modernized and available in several versions with significantly different capabilities, fires missiles from trucks and is designed to shoot down military aircraft and short and medium-range ballistic missiles.

One report in Israel had indicated that Russia received $1 billion from Syria in payment for the S-300.

Israel has made repeated efforts to persuade Moscow not to sell the S-300s to Syria, as it fears this would hinder its aerial capabilities against arms shipments to the Hezbollah terrorist group.

Russia announced it would upgrade Syria’s anti-air defense network and send the S-300 system there, following the downing of a Russian military aircraft in Syrian airspace.

US Secretary of State Mike Pompeo criticized Russia's delivery of the S-300 system to Syria and said it was a "serious escalation".