The United States is flying unmanned reconnaissance planes over Syria to monitor the regime's escalating crackdown on dissent, US defence officials told the NBC Television on Saturday.
The drones are being used to gather evidence on the Syrian security forces' violence against pro-democracy protesters that can be used to "make a case for a widespread international response", the US-based broadcaster quoted the unnamed officials as saying, DPA reported.
There was no official comment from Syria on the report.
The West has ruled out a Libya-style military intervention in Syria to stop 11 months of bloodshed.