US, Turkey launch operation to close Syria's northern borders

"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 kilometers," Kerry said in an interview with CNN.

The northern part of Syria along the Turkish borders has been a battle ground between Kurdish militias and Islamic State (IS) fighters. 

Under a joint US-Turkish plan, moderate Syrian rebels, trained by the US Army, would be expected to fight IS on the ground.

Under the strategy drawn up by Washington and Ankara, these rebels would also help coordinate airstrikes launched by the US coalition from Turkish air bases.

US President Barack Obama had also previously authorised the deployment of special forces against IS in an apparent deviation from an initial pledge not to have boots on the ground in the campaign.

Yet Kerry did not, during the interview, elaborate on whether the US would send ground troops to take part in the operation

At the same time Turkish officials, including Foreign Minister Feridun Sinirlioglu, said Ankara may launch a new military operation against IS in a matter of days. 

"When we wipe out IS from our borders, Turkey will be launching a wider military operation within the next few days," said Sinirlioglu. 

Sinirlioglu also mentioned close coordination between Turkey and the US to fight IS, which was a threat to Turkey and the whole world, Aljazeera reported him as saying. 

But Deputy Prime Minister Numan Kurtulmus declared no ground operation was planned.