Russia plans to deliver new air defense systems to Syria in the near future, Russia's Defense Ministry said on Wednesday, according to the RIA news agency.
No exact date was provided, however. It was unclear whether the comments referred to the advanced S-300 system which was developed by Russia.
The ministry added it plans to study a U.S. Tomahawk cruise missile captured by Syrian forces in a recent attack, in order to improve Russia's own missiles, the report said.
Russia and Syria signed a deal in 2010 for the S-300 system but the missiles have not been delivered because of Israeli pressure.
The Russians have deployed the S-300 around their own Tartus naval base on Syria's Mediterranean coast and the more advanced S-400 at their Hmeimim air base in western Syria.
Wednesday's announcement came a day after Defense Minister Avigdor Liberman said that Israel may strike the Russian-made S-300 anti-aircraft defense systems in Syria if they are used against Israel.
His comments followed a report in the Russian newspaper Kommersant which said that Moscow could soon start to deliver S-300 systems to Syria.
"One thing should be clear - if someone fires on our planes, we will destroy them," Liberman told the Ynet news website. "What's important to us is that the weapons defense systems that the Russians transfer to Syria are not used against us. If they are used against us, we will act against them."
Meanwhile, Russia's ambassador to Israel on Wednesday played down tensions between the countries over Israeli attacks in Syria, saying they were not the reason for Moscow's proposed supply of the advanced air defense system to Syria.
The ambassador also played down the risk of a physical confrontation between Russia and Israel over Syria.
"I can't imagine any such scenario," he was quoted by Reuters as having said in response to Liberman's threat. "We are mutually coordinating and updating about Syria ... So far, there have been no incidents between us, nor even hints at incidents, and I hope there will not be."
Russia has in the past provided Iran with the S-300 missile system. Russian President Vladimir Putin signed a decree in 2015 lifting a ban on the delivery of the S-300 to Iran, explaining that his decision was motivated by Iran's drive to find a solution in talks over its nuclear program.
The Pentagon said in March that Iran had tested and deployed the Russian-made anti-aircraft missile system.