Russian advanced military capabilities in Syria and the Mediterranean are behind NATO increasing its military presence in the region, according to Jens Stoltenberg.

Russian deployment of S-400 air defense systems in Syria has resulted in an increased North Atlantic Treaty Organization (NATO) presence in the region, NATO Secretary General Jens Stoltenberg said Tuesday.

"Russia is deploying advanced military capabilities both in Syria and the eastern part of the Mediterranean <…> That’s one of the reasons why we have increased our military presence in the eastern part of our alliance," Stoltenberg said.

Speaking ahead of a two-day NATO foreign ministerial meeting, Stoltenberg named the S-400 systems "part of a pattern where we see that Russia is developing what is called anti-access/area denial capabilities."

Russia deployed S-400 missile systems at its airbase in Syria following the downing of a Russian Su-24 Fencer by a Turkish F-16 fighter on November 24.