ERBIL - The US and Turkish forces carried out on Thursday their fourth phase of joint helicopter flight as part of a planned 'safe zone' in east of the Euphrates River in northern Syria.

Anadolu Agency reported that two US together with a couple of Turkish helicopters took off from Sanliurfa's Akcakale, in south of Turkey, where the two NATO allies have a joint operations center for their forces, explaining that they headed to the Syrian side of the border.

The US and Turkey had already conducted three joint helicopter flights with one ground patrol in the region.

Earlier on August 7, Washington and Ankara agreed to establish a safe zone in northern Syria so that the displaced civilians would be able to return to their places of origin safely.