Scant information is publicly available about Syria's chemical weapons program. According to intelligence estimates, the program is believed to have at least seven major installations and anywhere from 45 to 60 minor ones, controlling an estimated 1,000 metric tons of chemical weapons. A majority of these sites are located in the western core of the country. It is also believed that portions of the arsenal are highly mobile and able to be transported easily in ground vehicles. The regime is believed to have moved some of its stockpiles to the coastal region as the civil war has progressed. The two overarching fears pertaining to the chemical weapons are their use in Syria's civil war, or the possibility that they could fall into undesirable hands. The ongoing fighting has made both of these scenarios a real potential threat, forcing various Western governments to consider intervention. The military operation required to comprehensively seize all the chemical stockpiles in Syria would be complicated by many factors, including the quantity and geographic dispersion. Additionally, chemical weapons cannot necessarily be destroyed through strikes from precision-guided munitions. In other words, a ground force must physically secure the stockpiles and either remove the weapons from the country or go through a slow and deliberate destruction process there. Neither option is particularly feasible given that most of the chemical weapons are believed to be located amid the conflict's most intense fighting. Getting to these stockpiles would mean fighting through the regime's loyalist forces, which still control sizable air defense and armor assets, or going through territory held by numerous rebel groups, some of which are very hostile to Westerners. A comprehensive seizure of chemical weapons would necessitate a very robust combined arms operation, which U.S. military planners have estimated would require about 70,000-80,000 personnel. A recent U.S. acknowledgement that the Syrian regime may have used a small amount of sarin gas — previously considered a "redline" by the U.S. government — have raised questions on whether the United States may shift its military posture on the conflict. Nonetheless, the acknowledgement was carefully hedged, reflecting Washington's deep reluctance to get involved in Syria.