Anders Fogh Rasmussen of Belgium told EUobserver it wasn't the purpose of the trans-Atlantic defense alliance to solve every military crisis in the world.
"NATO cannot act as the world's policeman. We cannot travel from country to country to solve every conflict. It's simply not possible," he said. "The essence of being a defense alliance is that we are here to ensure the territorial defense of our member states."
As such, NATO recently installed a Patriot missile defense system in Turkey along the Syrian border to protect against rocket attacks after a spate of explosions perpetrated by the embattled regime of Syrian President Bashar Assad.
Rasmussen said international military intervention in Syria's 2-year-old conflict would have complicated matters, not made them better.
"It is my firm belief that any foreign military intervention would have unpredictable repercussions because Syrian society is very complicated, politically, ethnically, religiously and the regional context is very, very complex," Rasmussen said.
Notable deaths of 2014 [PHOTOS]
Russia bans Ukrainian fruits, vegetables