U.S. tells Turkey Syrian Kurdish YPG moving back to east of Euphrates: sources

In an early morning call, the two emphasized that the fight against Islamic State in Syria and Iraq would continue together, the sources said.

Syrian rebels backed by Turkish special forces, tanks and warplanes entered one of Islamic State's last strongholds on the Turkish-Syrian border on Wednesday, in Turkey's first major U.S.-backed incursion into its southern neighbor.

The role of the Syrian Kurdish YPG has been a sticking point between NATO allies Turkey and the United States. Washington backs the fighters against Islamic State in Syria. Turkey sees the YPG as an extension of the outlawed Kurdistan Workers Party (PKK), which has carried out a three-decade violent insurgency in its Kurdish southeast.

(Reporting by Asli Kandemir and Ece Toksabay; Writing by David Dolan; Editing by Edmund Blair)