Turkish Prime Minister Binali Yildirim
Turkish Prime Minister Binali Yildirim Reuters

Islamic State (ISIS) jihadists were expelled from their last positions along the Turkish-Syrian border, Turkey said Sunday, as Syrian forces again laid siege to rebel strongholds in war-torn Aleppo.

Turkish Prime Minister Binali Yildirim said his nation's forces and Syrian rebels had pushed back "terrorist organizations" on its southern border with Syria, depriving ISIS of a key transit point for recruits and supplies.

"From Azaz to Jarabulus, our 91 km border has been completely secured," Yildirim said during a televised speech while visiting the southeastern city of Diyarbakir.

The news comes as Syrian government troops renewed the siege of rebel-held parts of Aleppo on Sunday as Washington and Moscow failed to reach a deal on stemming violence in the country's devastating war.

The more than five-year conflict has become increasingly complex, involving not only regime and rebels, but international backers on both sides, Kurdish forces, jihadists and now Turkey.

The Britain-based Syrian Observatory for Human Rights said earlier "rebels and Islamist factions backed by Turkish tanks and warplanes" had taken several villages on the Turkish-Syrian border "after ISIS withdrew from them, ending ISIS's presence... on the border."

Ankara began an operation inside Syria on August 24, using tanks and war planes to back opposition fighters with special forces also providing support.

Turkey's success is likely to deliver a blow to the Syrian Kurdish YPG, which has been gaining territory in Syria's north after working with the US-led coalition against the jihadist force.

But Ankara considers the YPG a "terrorist" group and has been alarmed by its expansion along the border, fearing the creation of a contiguous, semi-autonomous Kurdish region in northern Syria.

That position puts Turkey at odds with the United States, which views the YPG as a key ally in its fight against ISIS.

President Recep Tayyip Erdogan has said Turkey would not allow a "terror corridor" on its southern border.

With Turkey's rapid success in less than two weeks, his position looks stronger with territory in between the two Kurdish "cantons" of Afrin and Kobane now in the hands of Ankara-backed rebels.

The loss of the Turkish border will also deprive ISIS of a key transit point for recruits and supplies, though the group continues to hold territory in both Syria and Iraq.

AFP contributed to this report.