White House Press Secretary Jay Carney could not confirm recent news reports about the missile strikes, but noted that "if true, this would be the latest desperate act from a regime that has shown utter disregard for human life."
"Trajectory and distance traveled indicate they were Scud-type missiles," the NATO official told Reuters on the condition of anonymity.
It remains unclear which specific rebel positions, if any, were hit by the barrage of Scud missiles. What is clear is the strikes were the first time government forces loyal to the Assad regime have used weapons of that magnitude during the country's civil war.
"The idea that the Syrian regime would launch missiles within its own borders at its own people is stunning, desperate," Carney added.
Assad's forces have mercilessly targeted rebel strongholds in northern Syria and across the country throughout the now 20-month conflict, zeroing in on rebel positions with attack helicopters, heavy artillery and fighter jets.
Despite such attacks, rebel forces have been able to battle back against government troops in Aleppo and elsewhere in the country, recently taking the fight to Assad's doorstep in Damascus.
Reports of the Scud strikes come a day after the Obama administration officially recognized the The Syrian Opposition Coalition, the political arm of the rebel movement, as the legitimate government authority in the country.
That recognition paves the way for Washington to provide weapons and armed support to rebel forces, a break from the White House's initial policy of limiting U.S. support to Syrian rebels to non-lethal equipment.
However, Assad's willingness to use Scud missiles against rebel forces also raises the specter of possible chemical weapons being introduced onto the battlefield by the regime.
The Soviet-surplus Scud missiles in Assad's arsenal can be outfitted with various chemical weapon agents, such as sarin gas, mustard gas and cyanide onto the weapon's warheads.
Earlier this month, President Obama made "absolutely clear" during a Monday speech at the National Defense University in Washington that the use of chemical weapons by the Assad government against rebel fighters "would be totally unacceptable" and trigger an immediate and overwhelming response by the United States.
Recent U.S. intelligence showed Assad's forces outfitting air-to-ground bombs with sarin gas at two airfields in Syria, prompting the Pentagon to begin drafting plans for preemptive military strikes against the country's chemical weapon stockpiles.
"The more information and intelligence you have, the more clarity you can bring to options you may decide to use," a department official told CNN last Friday.
"You would expect new information like this to drive an update of options," the official said.