After first launching strikes
After first launching strikes against IS in Iraq in August, Washington has built a coalition of allies to wage an aerial campaign against the group.
Britain and France have joined the strikes in Iraq and five Arab nations -- Bahrain, Jordan, Qatar, Saudi Arabia and the United Arab Emirates -- have taken part in the raids in Syria.
Turkey's parliament last week authorised the government to join the campaign, but so far no plans for military action have been announced.
Ankara warned on Saturday though that it would not hesitate to strike back if IS attacked Turkish troops stationed in a tiny exclave inside Syria containing the tomb of Suleyman Shah, the grandfather of the founder of the Ottoman dynasty Osman I.
The patch of land around the tomb is considered Turkish territory under a 1920s treaty and about 40 lightly armed Turkish soldiers are based there.
Syrian media on Sunday accused Ankara of using the tomb as an excuse to intervene in the country.
