SET amid the rolling plains outside Aleppo, the town of al-Safira looks like just another battleground in Syria's vicious civil war. On one side are lightly armed rebels, on the other are government troops, and in between is a hotly contested no-man's land of bombed-out homes and burnt-out military vehicles.
The fight for al-Safira is no ordinary turf war, however, and the prize can be found behind the perimeter walls of the heavily guarded military base on the edge of town.
Inside what looks like a drab industrial estate is one of Syria's main facilities for producing chemical weapons. Among its products is sarin, the lethal nerve gas that the regime is now feared to be deploying in its bid to cling to power.
Last week, Washington said for the first time that it had evidence of sarin being used in "small" amounts during combat operations in Syria, a move that President Barack Obama has long warned is a "red line" that President Bashar al-Assad must not cross.
But as the West now ponders its response, the fear is not just that President Assad might start using his chemical arsenal in much greater quantities. Of equal concern is the prospect of it falling into even more dangerous hands – a risk that the stand-off at al Safira clearly illustrates.
Among the rebel lines in al-Safira flutters the black flag of the Al Nusra Brigade, the jihadist group that recently declared its allegiance to al-Qaeda. Known for their fighting prowess honed in Iraq, they are now taking the lead in nearly every frontline in the Syrian war, and earlier this month, pushed to within a mile of al-Safira, only for the Syrian troops to gain ground again last week.
Should the tide of battle turn in Al Nusra's favour again, there is the possibility of the West's worst-case scenario unfolding: Syria's weapons of mass destruction falling into al-Qaeda's control.
More than 500 times as toxic as cyanide and deadly in milligram-sized doses, a single canister of sarin could unleash carnage.
Such grim possibilities are uppermost in the minds of Western officials as they try to work out how to prevent Syria's vast chemical stockpiles being unleashed, be it by Mr Assad on his own people, or by his more extreme opponents in the outside world.
As the Syrian uprising has intensified in the past year, the regime has been secretly moving its stockpiles to dumps all over the country, much of which it barely controls anymore.
"The West may be saying, 'A red line has been crossed, let's do something'. But the question is what exactly can they do?" said Dina Esfandiary, an expert on Syria's WMD programme with the International Institute for Strategic Studies in London.