"Today we will discuss all the security challenges in our eastern and southern neighborhoods. To the East the more assertive Russia used force to change borders and intimidate neighbors. To the South extremism has reached a level unprecedented in modern times," Stoltenberg said during a NATO foreign ministers session in Turkey.
Stoltenberg said the alliance will adapt to the new threatening environment by reinforcing its defense to levels only seen during the Cold War.
"In this more dangerous security environment NATO will continue to protect and defend each ally against any threats. That is why we are adapting to a new environment and implementing the greatest reinforcement of the collective defense system since the days of the Cold War," he added.
On Wednesday, Russia's Permanent Mission to NATO said in a statement that the alliance promoted a distorted picture of its relations with Moscow and attempted to persuade the public that its efforts contributed to European security. The mission pointed that in its remarks, the bloc silenced criticism about its military actions in the Balkans, Afghanistan and Libya.