If used, the weapons could open up a new and extremely deadly chapter in Syrian President Bashar Assad's nearly year-long campaign to quash anti-government forces fighting to oust the longtime leader from power.
“If Assad is transferring chemical weapons from secure sites to the battlefield, it significantly raises the risks that they will be used or that control over these weapons could be compromised," Sens. John McCainJohn McCainSchumer calls for Senate probe into Russian interference Ukrainians made their choice for freedom, but now need US help White House orders intelligence report of election cyberattacks MORE (R-Ariz.), Joe Lieberman (I-Conn.) and Lindsey GrahamLindsey GrahamSchumer calls for Senate probe into Russian interference Senators move to protect 'Dreamers' The Hill's 12:30 Report MORE (R-S.C.) said in a joint statement.
"These are unacceptable risks for the United States and the entire international community, and they would threaten our vital national security interests," according to the statement.
White House deputy press secretary Josh Earnest told reporters on Friday that recent developments in Syria was proof positive that the international community needed to take action to end the crisis in the country.
"If there was any doubt before yesterday about the need for a coordinated international response at the United Nations, that doubt has been eliminated," Earnest said.
Rep. Mike Rogers (R-Mich.), head of the House Permanent Select Committee on Intelligence, warned the weapons would not only pose a threat to Syrian civilians but to the United States and its allies, should terror groups like al Qaeda get a hold of the deadly ordnance.
"I am very concerned that as the situation in Syria deteriorates, these weapons could fall into the wrong hands," Rogers said.
DOD press secretary George Little told reporters on Friday that Syrian forces were in firm control of their chemical weapon stockpiles. But if Assad's forces did use chemical weapons on rebel fighters or civilians, the move "would cross a serious red line," Little said.
"We believe that the Syrian government has a very serious responsibility to protect its stockpiles of chemical weapons," he added. "We would, of course, caution them strongly against any intention to use those weapons."
But Rogers noted that there was no way the Assad regime could guarantee the safety of those weapons, given the extremely volatile situation on the ground in Syria.
"We don’t have to look back far in history to see that, even with the best of information, it cannot be predicted when a regime like Assad’s might collapse," he said.
U.S. and NATO forces were unprepared to secure Libya's stockpiles of shoulder-fired rockets after former Libyan dictator Moammar Gadhafi was killed last March by anti-government rebels in that country.
Last October, U.S. intelligence allegedly picked up "worrying indicators" that the missiles, similar to the famous Stinger anti-aircraft missile that the United States supplied to the Afghans to defeat the Soviets, had made their way to Islamic terror groups operating in the region.
At the time, Africa Command chief Gen. Carter Ham said some of the weapons had already been smuggled out of Libya by terror groups operating in North Africa and the Mideast.
The problem has been compounded in Syria due to elements from al Qaeda's Iraqi faction infiltrating the country, looking to take advantage of the current political unrest.
However, Pentagon officials are adamant that none of those al Qaeda operatives have made their way inside the Free Syria Army or other rebel groups fighting the Assad government.
Sen. Jeanne Shaheen Jeanne ShaheenDems push for panel to probe Russian interference in election Hoyer pushes White House for briefing on Russian election interference This Week in Cybersecurity: Dems press for information on Russian hacks MORE (D-N.H.) in March pressed Central Command chief Gen. James Mattis on the issue of Syria's chemical weapon stockpiles during a Senate Armed Services Committee hearing.
“What happens if those weapons are left unsecured — could they potentially disappear and be used throughout the region?” Shaheen asked Mattis at the hearing. “Is there any suggestion that Assad might actually use these weapons against the people of Syria?”
Mattis said it was unlikely that Assad would use those weapons on his own people.
—This story was updated at 2:05 p.m. to include comments from George Little.