AP News Guide: Turkish-US deal may have far-reaching effect on Islamic State group, Syrian war

1BEIRUT - In a major policy shift, Turkey has agreed to allow the United States to use a key base to launch airstrikes against the Islamic State group and agreed on the outlines of a plan to rout the extremists from a stretch of Syrian territory along the Turkish border.
2A 110-kilometer (68-mile) stretch along the Turkish border in Syria is under Islamic State control.
3Turkey and the U.S. agreed to push the group from there, replacing its militants with relatively more-moderate Syrian insurgents and eventually establishing a safe zone where tens of thousands of displaced Syrians could live.
4The U.S. says the plan does not include the imposition of a no-fly zone, nor Turkish or U.S. troops on the ground.
5But Turkish Prime Minister Ahmet Davutoglu said air cover will be provided.
6The deal further embroils Turkey, a key NATO ally, in Syria's civil war, and also catapults it into a front-line position in the global war against the Islamic State group.
7Turkey's involvement could have far-reaching consequences.
8An Islamic State-free zone along the Syria-Turkish border - through which the group has smuggled foreign fighters, oil and other goods for the past year - would strangle the militants in Syria, weakening the group.
9Use of Turkey's Incirlik base would allow U.S. warplanes closer access to Islamic State targets in northern Syria.
10But a Turkish ground campaign sets up a potential conflict with U.S.-backed Kurdish forces in the area, possibly emboldening other Turkey-backed hard-line Islamic groups.
11The Islamic State group is a significant threat to Turkey, particularly after a deadly suicide bombing in the country's south that authorities blamed on the group earlier this month.
12But Turkey's more primary concern is to prevent the establishment of a Kurdish state along its southern border and to topple Syrian President Bashar Assad's government.
13Syrian Kurds are concerned that Ankara likely is trying to limit advances by Syrian Kurdish forces and trying to steer Washington away from the YPG, the main Kurdish fighting force in Syria.
14Turkey called a meeting of its NATO allies Tuesday to discuss threats to its security and its airstrikes.
15A Turkish official has said Turkey and the U.S. are discussing "the formation of a de-facto safe zone" which would facilitate the return of refugees, adding that Turkey was prepared to provide assistance including "air support."
16The zone likely would stretch between the towns of Azaz to the west and Jarablous to the east, and it probably would reach as far south as al-Bab.
17Close to 2 million Syrian refugees have fled to Turkey.
18Many may be encouraged to return to Syria under U.S. and Turkish protection.
19However, in the absence of a no-fly zone to neutralize Assad's warplanes, it is not clear how the possible buffer zone could be considered a safe haven.