US security and intelligence officials fear al-Qaida may use Syria as a launching pad for attacks against the US and Western countries.
They have said in their intelligence reports that militants from Pakistan have been gathering in the volatile country and regrouping for a major attack against the West.
CIA Director John O Brennan told a House panel recently that al-Qaida has been recruiting militants from Pakistan, planning attacks inside Syria, and using Syria as a launching pad.
At the moment, dozens of militant groups are operating across Syria, which is one reason the US and its Western allies have refused to give weapons to the Syrian rebel fighters. The US and its allies fear that the weapons may land in the hands of extremists and militant groups that could be ultimately used against the interests of the US and its allies.