Brussels, June 19 (RHC)-- The NATO secretary general says the Western military alliance is carrying out its "biggest" military reinforcement since the Cold War in what it calls an attempt to tackle the rising security threats in the region.

NATO is facing a new security environment, both caused by violence, turmoil, instability in the south -- ISIL in Iraq, Syria, North Africa -- but also caused by the behavior of a more assertive Russia," said Jens Stoltenberg in Poland's western city of Zagan on Wednesday.

Stoltenberg accused Moscow of having "used force to change borders, to annex Crimea and to destabilize eastern Ukraine." He arrogantly added: "There NATO has to respond. We are responding, and we are doing so by implementing the biggest reinforcement of our collective defenses since the end of the Cold War."

Stoltenberg made the remarks during the first exercise of NATO's Spearhead Force in Zagan, adding that the new rapid reaction unit plays a significant role in the alliance's military equations.

"The Spearhead force is a key element of this reinforcement, and it's great to see that it's functional, and that it's exercising here in Poland," he pointed out.

Earlier in the day, Polish Defense Minister Tomasz Siemoniak rehashed the West's anti-Russian rhetoric, calling on NATO to expand its military presence in the region.

"Those who are responsible for the security of their countries should do their job irrespective of someone's words or threats," he pointed out in reference to the recent remarks by Russian President Vladimir Putin about adding over 40 intercontinental ballistic missiles to the country's nuclear arsenal in 2015.

Putin had also warned that the new missiles "will be capable of penetrating any, even the most technologically advanced, anti-missile defense systems."

Meanwhile, Putin's spokesman Dmitry Peskov stressed that Moscow does not aim to arouse security concerns in the West, saying that the announced plan is part of Russia's "strategic security" and just serves as a deterrent.