The U.S.-backed SDF, led by the Kurdish YPG militia, said such a zone must have "international guarantees...that would prevent foreign intervention", in an apparent reference to neighbouring Turkey. The SDF statement said it hoped to ensure stability at the border region by reaching agreements with Turkey, which has vowed to crush the YPG.
Trump, who announced he was pulling U.S. troops out of Syria last month, suggested in a tweet on Sunday creating a safe zone without elaborating. The SDF fears the U.S. move to withdraw will give Turkey the opportunity to mount a new assault.
President Tayyip Erdogan said on Tuesday he had discussed a safe zone which Turkey would set up inside Syria along the length of their border, during a phone call with Trump.
U.S. arming of the YPG, the main American partner in the fight against Islamic State, has infuriated NATO ally Turkey. Ankara deems the Syrian Kurdish fighters terrorists linked to the Kurdish PKK movement that has waged a decades-long insurgency on Turkish soil. (Reporting by Ellen Francis; Editing by Catherine Evans, William Maclean)