YEKATERINBURG, November 25. /TASS/. S-400 missile systems, deployed to Turkey, will be returned to Russia after Russia’s Aerospace Forces’ operation in Syria is over, their sale is not planned, Russian presidential aide on military technical cooperation Vladimir Kozhin said Wednesday.

"There’s no talk about sale. It’s our system that will ensure security; when our units return from there, the system will be returned as well. No one has thought or spoken about any sales. There are no such plans," Kozhin said.

Asked about the interest of the Chinese side in the S-400 systems, he said that "talks are ongoing; we will announce it when contracts are signed."

Kozhin added that talks with China on Su-35 aircraft supplies to China are continuing.

"This is complex technology, talks are rather difficult. The talk is about the delivery of dozens of machines," he said

On Wednesday Russian President Vladimir Putin told the media that Russia will employ every single resource available, including the S-300 system, to ensure the safety of flights over Syria. Before that, the Russian defense minister noted that Russia's S-400 Triumf air defense systems will be moved to the Hmeimim air base in Syria.

On Tuesday, a Russian Sukhoi-24M bomber was downed with an air-to-air missile launched from an F-16 fighter of the Turkish Air Force. One of the pilots died and the other was rescued and brought to the Russian base. A Russian Mi-8 helicopter was destroyed during the search and evacuation operation. One Marine serving in the army on contract was killed.

Turkey claims that the downed plane had violated its air space. The Russian Defense Ministry says the Sukhoi-24M stayed over Syria all the time and it was the Turkish fighter that violated the border during the attack.

The Russian General Staff has warned that Russia will be destroying all potentially dangerous targets over Syria and moved towards the Syrian shores its guided missile cruiser The Moskva armed with the Fort system (the sea-launched equivalent of S-300).