The United States said Tuesday it does not intend to coordinate with the government of President Bashar al-Assad on targeting Islamic State militants on Syrian territory.
"There are no plans to coordinate with the Assad regime as we consider this terror threat," White House spokesman Josh Earnest said, after Syrian officials demanded Washington ask permission for any action over its territory.
Earnest spoke amid reports that US spy planes and drones had already started flights over Syria to collect intelligence as President Barack Obama contemplates air strikes against IS militants who have already come under US attack in Iraq.
Earnest dismissed Syrian demands that it be notified of any US activity and offers to work with Washington to combat terrorism, saying that the United States did not even recognize the Assad regime as the legitimate rulers of Syria.
For more than two weeks, US warplanes have been carrying out a limited air campaign against IS militants in Iraq, with most of the bombing raids conducted near Mosul dam.
The grisly murder of American journalist James Foley by IS jihadists and mounting concern in the West over the threat posed by the extremists has prompted speculation that Washington may expand its air war to Syria.
Earnest reiterated on Tuesday that Obama had so far taken no decision to conduct air strikes in Syria.