"We don't have any intention to intervene militarily in Syria," NATO chief Anders Fogh Rasmussen said in a speech from the alliance's headquarters on Monday.
The United States, NATO and the rest of the international community "will send a unified and clear message" that a diplomatic strategy is the right one for Syria, he added, according to Reuters.
The alliance chief also dismissed comparisons between the ongoing Syrian conflict and the 2011 mission to provide U.S. and NATO armed support to the uprising in Libya.
That effort, dubbed Operation Unified Protector, ended with the death of longtime Libyan strongman Moammar Gadhafi.
The Libya action, according to Rasmussen, was backed by a United Nations mandate to protect Libyan civilians caught in the carnage and enjoyed widespread support from regional powers.
"None of these conditions are fulfilled in Syria," he said Wednesday. "There is no United Nations mandate, there is no call on NATO to intervene in Syria, even the opposition in Syria does not ask for a foreign military intervention."
Rasmussen's comments come a day after the White House rejected requests from Syrian rebel leader Moaz al Khatib to use U.S. air power to take out Syrian President Bashar Assad's fleet of warplanes.
NATO rejected al Khatib's demand to use the battery of Patriot missile defense systems in Turkey against government targets in Syria.
Washington approved the deployment of the missile defense systems to Turkey, to assist Ankara's effort to keep the Syrian war from bubbling over into the country.
Assad's forces have used jet fighters, as well as long-range artillery and other heavy weapons, in an attempt to bludgeon the Syrian opposition into submission.
However, rebel forces based in Aleppo and Homs have battled back over the past two years, taking the fight to Assad's doorstep in Damascus.
But al Khatib and other rebel leaders claim they cannot make their final push to topple the Assad regime without military support from Western powers, including the United States.
That argument has begun to garner a number of supporters on Capitol Hill from both sides of the aisle in recent weeks.
Last week, Senate Armed Services Committee chief Sen. Carl LevinCarl LevinFor the sake of American taxpayers, companies must pay their fair share What the Iran-Contra investigation can teach us about Russia probe Senate about to enter 'nuclear option' death spiral MORE (D-Mich.) joined with Senate Republicans, demanding Obama take military action to end the Syrian conflict.
Previously, the influential Democrat had backed the administration’s strategy of using sanctions and diplomacy to end the conflict.
Specifically, Levin and Sen. John McCainJohn McCainTrudeau, Trump speak for second night about US-Canada trade McCain: China has done ‘nothing’ on North Korea Trump administration weighing order to withdraw from NAFTA MORE (R-Ariz.) pressed the Obama administration to establish a “safe zone” along the Turkey-Syria border for Syrian refugees, using the Patriot missiles to defend the zone against Assad's jets.
American and allied warplanes must also begin conducting “precision airstrikes” against Assad's network of anti-aircraft defenses in Syria, Levin and McCain argued.
Finally, the lawmakers recommended that the administration provide more "tactical intelligence" to rebel forces in Syria, as well as more medical and humanitarian supplies.
“We believe there are credible options at your disposal, including limited military options, that would require neither putting U.S. troops on the ground nor acting unilaterally,” the lawmakers wrote.
On Tuesday, Pentagon press secretary George Little brushed aside such demands, saying "the [White House] policy remains very clear" in its continued dedication to a peaceful, diplomatic solution to the civil war in Syria.