MOSCOW, March 15. /TASS/. The remaining Russian contingent in Syria will be safely protected, including by advanced air defense systems, Kremlin chief of staff Sergey Ivanov said on Tuesday.

"We will leave [in Syria] a full safe protection of the remaining contingent, its smaller part - protection from the air, the sea and the ground," Ivanov told reporters responding to a question if Russia will leave its S-400 air defense systems in Syria.

"To ensure security, including from the air, state-of-the-art air defense systems are needed," Ivanov said.

Russia will step up the fight against terrorism, he stressed, but added that there is no more need for such a contingent that used to be in Syria. "At the moment, I think the first aircraft have already got off the ground and are en route to the motherland," he said.

The defense ministry said earlier in the day that the first group of Russian planes has left the Hmeimim air base in Syria for their permanent locations in Russia. "The group consists of the leader plane - a Tupolev-154 liner - and multi-role bombers Sukhoi-34," the ministry said.

President Putin ordered on Monday to start withdrawing the main part of Russia’s forces from Syria as of March 15. He said the tasks assigned to the military were generally fulfilled.

Russia has been carrying out an anti-terror operation in Syria since September 30, 2015 at the request of Syrian President Assad.