Brussels: NATO Secretary General Anders Fogh Rasmussen Monday made an appeal for closer collective defence, community of nations and collective engagement.
The NATO chief made the call while delivering a speech at Carnegie Europe, a well-known think tank, as he said the NATO now "see challenges on a scale we have not seen for over two decades, and they will endure for years to come", Xinhua reported.
"To the East, there is Russia," said Rasmussen, adding that although the NATO has tried long and hard to build a partnership with Russia, Russia regrettably has rejected the efforts to engage.
Instead, Russia considers NATO, and the West more broadly, as an adversary, Rasmussen said.
"Russia has trampled all the rules and commitments that have kept peace in Europe and beyond since the end of the Cold War," he said.
Rasmussen said to the south the challenge is the terrorist group of the so-called Islamic State, noting this group poses even more of a danger as it risks exporting terrorists to our countries and it also controls energy assets.
"Our defence capabilities, military posture and political will must send a clear signal to any potential aggressor," he said.
He also reiterated the transatlantic bond between "Europe and North America", saying the two sides are at the core of the global community, and the relationship is the "bedrock of our shared security and our common values."
Noting the NATO has to be willing and able to use both soft and hard power to protect and promote its values, he said any lasting solution to a crisis will always be political, and diplomacy remains vital.
And if they fail to defend freedom and democracy, forces of oppression will seize the opportunity.