Russian President Vladimir Putin has given Turkey a “stark warning” by deploying its most advanced air defense system to the Hmeymim Air Base in Syria following Turkey’s downing of the Russian Su-24 jet on Monday. A Russian source said that Russia is exploring the possibility of sending another 10-12 air jets to the base for further reinforcement.

Henceforth one of the 24 Russian bombers will be accompanied by a military jet, say Russia’s defense sources.

The deployment of the S-400 military system to Syria was announcemed a day after the Turkish F-16 fighter jets shot down the Russian jet that was taking part in Russia’s counterterrorism campaign in Syria. Ankara claims that the Su-24 jet violated Turkish airspace were  refuted by Russia that maintains that the downing of the plane was a military and political provocation.

Russia’s Defense Ministry points to three goals in the attack of the jet: (1) Turkey wanted to scare Russia; (2) they sought to decrease the intensity of airstrikes on the oil tankers ISIS militants use to smuggle oil from the territory they control; (3) they wanted to offer ISIS slight hope that militants would be able to continue to fight.

On his part, Turkish President Recep Tayyip Erdogan says he does not wish to see an escalation of friction following the downing of the Russian jet, explaining that Turkey was only interested in defending its own security and border rights against violations. Speaking to a business conference in Istanbul, Erdogan said that the Russian jet was struck while in Turkish air space but fell on Syrian ground though fallout from the crash fell into Turkey and injured two Turkish citizens.