A government official said there was no new agreement over the use by the United States of the Incirlik air base in southern Turkey, which US air forces already use for logistical and humanitarian purposes.
"There is no new agreement with the United States about Incirlik," the official, who asked not to be named, told AFP in Ankara.
"Negotiations are continuing" based on conditions Turkey had previously laid out such as a safe zone inside Syria backed up by a no-fly zone, the official added.
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"There is no change in our position," the official said.
A senior US defence official said Sunday that Turkey has granted the US forces access to its air bases, including Incirlik, for the bombing campaign against IS.
"Details of usage are still being worked out," the US official told AFP on condition of anonymity.
Located in southern Turkey in Adana province a short distance from the Syrian border, Incirlik would be an ideal start point for US forces to launch air strikes against IS inside Syria.