The Wall Street Journal reports: Turkish and American military forces launched a major offensive in northwestern Syria against Islamic State militants early Wednesday as they try to sever the extremist group’s vital supply routes and deter Kurdish fighters from seizing a key border town, according to officials from both countries.

Turkish special forces, aided by American military advisers, U.S. drones and Turkish artillery units, moved into northern Syria before dawn as part of the coordinated campaign to push Islamic State out of a strategic town on the Euphrates River, officials said.

Turkish jets bombed Islamic State forces inside Syria, according to Turkey’s state-run Anadolu news agency, in what are believed to be the first airstrikes by Turkey inside Syria since November, when Turkish pilots shot down a Russian warplane that briefly strayed into Turkish airspace. Turkish tanks also moved into Syria as the offensive gathered momentum early Wednesday, the news agency said.

Meanwhile, hundreds of Turkish-backed Syrian rebels were massed at the border, poised to retake Jarabulus, one of Islamic State’s last remaining gateways used by the group to ferry reinforcements and supplies from Turkey into its de facto capital in Raqqa.

Turkish artillery units had been pounding Islamic State forces holding the Syrian town for two days as the military — shaken by last month’s thwarted coup attempt — looks to re-establish its role as a key player in the fight on its doorstep.

U.S. drones based at Incirlik Air Base in southern Turkey are carrying out surveillance missions over Jarabulus, and American special operations forces are working with Turkish military officers on the Turkish side of the border to plan the offensive, officials said. [Continue reading…]