MOSCOW, November 26. /TASS/. Russia’s S-400 air defense system has entered duty at the Hmeimim air base accommodating Russia’s air and space group in Syria, Russian Defense Ministry spokesman Igor Konashenkov has told the media.

"In accordance with the decision of Russia’s Supreme Commander-in-Chief an air defense complex S-400 has been promptly delivered to the Russian air base in Hmeimim in Syria. It has been deployed and entered combat duty to provide air defense for the area," he said.

Konashenkov also noted the Russian Defense Ministry is surprised over the US reaction to the deployment of an S-400 air defense system in Syria.

"The reaction by the US side to this move causes a surprise," the spokesman said.

The general cited a statement by the US embassy in Moscow, which said that the deployment of the S-400 system would further complicate the already tense situation in the sky over Syria.

"What can be said in this regard? We shared this opinion until Tuesday as we were confident that our planes destroying the facilities of the Islamic State [terrorist organization outlawed in Russia] were guaranteed against attacks from the so-called US-led anti-IS coalition," Konashenkov said.

Russia has also taken other measures to defend its aviation in Syria. Specifically, the missile cruiser Moskva went on combat duty from 10:00 a.m. Moscow time (07:00 GMT) on Wednesday to provide air defense for the Russian air base in Syria. The Moskva missile cruiser is armed with the Fort system, which is the naval version of the S-300 antiaircraft missile complex, the general said.

"Now we’ll ensure the defense of our air group’s aircraft in operations against IS terrorists and other terrorist groupings by more reliable means," the Russian Defense Ministry spokesman said.

An F-16 fighter jet from the Turkish Air Force shot down a Russian Su-24M bomber on Tuesday. Ankara claims the Su-24M bomber violated the Turkish air space in the area of the border with Syria.

However, Russia’s Defense Ministry has said the Su-24M plane stayed exclusively over the Syrian territory and "there was no violation of the Turkish air space."

Russian President Putin has warned that the attack on the bomber will have "serious consequences" for the Russian-Turkish relations. According to Putin, the Turkish Air Force’s attack on the Russian combat plane that took part in the operation against terrorists in Syria and posed no threat to Turkey is a "stab in Russia’s back."

The crew of the Su-24M bomber managed to eject but one of the pilots was killed by gunfire from the ground. The second pilot was rescued and taken to the Russian air base. The rescue operation involved two Mi-8 helicopters. One of the helicopters came under fire and made a crash landing and a contract soldier was killed. The helicopter’s other personnel were evacuated to a safe place. The Mi-8 helicopter damaged by gunfire was subsequently destroyed by mortar fire from the territory controlled by militants.