"The work was finished a day ago," Russian Defense Minister Sergei Shoigu told President Vladimir Putin during an October 2 meeting broadcast on Rossia-24 TV.
Shoigu contended that the system would improve the security of Russian military personnel in Syria and said it will take three months to train the Syrian military to operate the new system.
Putin ordered the military to supply the system to Syria after the downing of a Russian reconnaissance aircraft last month by Syrian antiaircraft fire in an incident that Russia blamed partly on Israel, which was staging air raids on Iranian targets in Syria at the time.
Footage of the delivery of S-300 (S-300PM2) surface-to-air missile system to Syria.The missile system being unloaded from an An-124-100 Ruslan strategic airlift jet aircraft at the Hmeymim air base. pic.twitter.com/FaDWGRbmAW— Military Advisor (@miladvisor) October 3, 2018
All 15 Russian crew members were killed in the incident. Russia claims that the Israeli jet pilots dodged behind the Russian plane to avoid being hit by the antiaircraft fire.
Israel voiced regret afterward, but blamed Syrian incompetence for the incident and said it would continue bombing Iranian military targets in Syria.
"We have not changed our strategic line on Iran," Israeli Education Minister Naftali Bennett, a member of Prime Minister Benjamin Netanyahu's security cabinet, said on October 2.
"We will not allow Iran to open up a third front against us. We will take actions as required," he told Israel Radio.
In Washington, State Department spokeswoman Heather Nauert said she could not confirm Russia's claim that the S-300 was delivered.
"I cannot confirm that that is accurate. I hope that they did not," she told a press briefing. "That would be, I think, sort of a serious escalation in concerns and issues going on in Syria."
Shoigu at the meeting in Moscow also said the Russian military had added equipment in Syria for "radio-electronic warfare" and now "controls" the airspace in the area used for strikes on Syrian soil.
Along with upgrading Syria's missile-defense system, Moscow last month announced that Russia would begin jamming the radars of hostile warplanes in regions near Syria, including over the Mediterranean Sea, to prevent further incidents that could cause harm to its troops.
A Russian lawmaker this week said that 112 Russian military personnel have been killed so far in Syria since it started actively intervening in the conflict in 2015.
Russian and Iranian military support for Syrian President Bashar al-Assad have been critical in helping turn the tide of the war in his favor. Over 400,000 people have been killed in the conflict and millions more displaced from their homes.