Turkey's ten day old military's offensive into north-eastern Syria is deepening the Syrian conflict by pitting Turkish military aims against those of the US, which is a fellow NATO member state.
Turkish tanks and troops entered crossed the border on January 20th and are fighting alongside Free Syrian Army soldiers to oust Kurdish YPG fighters from the Afrin region.
But the United States has around 2,000 military personnel in northern Syria supporting an umbrella group of fighters, dominated by the YPG, which drove Islamic State from its Syrian strongholds last year.
And Turkey, which considers the YPG to be a terrorist organisation, has called on Washington to end its military support for the group and to pull back from the Manbij region where some of its troops are stationed.
CNN quoted the U.S. Central Command chief General Joseph Votel as saying that the United States has no plans to withdraw troops stationed near Manbij.
Pulling U.S. forces from Manbij is "not something we are looking into", he said on Sunday during a trip to the Middle East.
Foreign Minister Mevlut Cavusoglu said on Saturday the United States "needs to break its link with the terrorist organisation and make them drop their weapons completely. They need to collect the weapons they gave, they need to withdraw from Manbij immediately."