U.S. Secretary of State John Kerry said on Tuesday the United States is starting an operation with Turkey to finish securing the northern Syrian border, an area that Islamic State militants have used as a lucrative smuggling route.
"The entire border of northern Syria - 75 percent of it has now been shut off. And we are entering an operation with the Turks to shut off the other remaining 98 km (61 miles)," he said in an interview with CNN.
Kerry arrived in Paris on Monday to pay respects to victims of Friday's militant attacks that killed 129 people.
The area where the operations would take place is now controlled by the radical Islamists. The United States and Turkey hope that by sweeping Islamic State, also frequently called Daesh, from that border zone they can deprive it of a smuggling route which has seen its ranks swell with foreign fighters and its coffers boosted by illicit trade.
Under a long-discussed joint U.S.-Turkish plan, moderate Syrian rebels, trained by the U.S. army, would be expected to fight Islamic State on the ground and help coordinate air strikes by the U.S. coalition, launched from Turkish air bases, under the strategy drawn up by Washington and Ankara.
Diplomats familiar with the plans have said cutting off one of Islamic State's lifelines could be a game-changer in that corner of Syria's complex war. The core of the rebels, who number less than 60, would be highly equipped and be able to call in close air support when needed, they say.
"We are in a common struggle with the U.S. against Daesh and in the coming days some steps will be taken together," a Turkish official told Reuters, declining to comment further.