Erdogan has in the past warned of new military operations against the YPG along the Syrian border and if necessary into northern Iraq.

Expanding Turkey's military campaign into the much larger Kurdish-held territory east of the Euphrates would risk confronting troops of NATO ally the United States, that are deployed alongside a YPG-dominated force there.

The YPG has been Washington's main ally against Islamic State in Syria, infuriating Ankara which sees the Kurdish force as an extension of a militant group waging a decades-long insurgency in southeast Turkey.

Erdogan's comments come a week after he and Russia's Vladimir Putin announced a deal under which Russian and Turkish troops will enforce a demilitarised zone in north-west Syria's Idlib region.

Tensions between Russia and Israel over the Syrian conflict have reignited after Russia's Defence Ministry issued a harsh critique of Israel's role in the downing of a Russian plane in Syria last week, despite previous efforts to smooth over the rift.

Releasing the results of an inquiry into the incident, in which a Russian IL-20 plane was shot down on September 17 by a Syrian anti-aircraft missile during an Israeli airstrike, Russian Defence Ministry spokesman General Igor Konashenkov said the actions of Israeli fighter pilots showed "a lack of professionalism, or, at a minimum, criminal negligence".

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Fifteen Russian servicemen were killed on board the plane, one of the highest tolls in a single incident for regular Russian troops since Russia's military intervention in Syria three years ago.

By failing to give adequate warning of its intention to strike in the area, in the vicinity of Russia's main Hmeimim military base in Syria, Israel violated Russian-Israeli agreements intended to reduce conflict in their air operations in Syria, Konashenkov said. He said an Israeli jet had used the Russian plane as cover, thereby exposing it to Syria's anti-aircraft fire.

Konashenkov called Israel's behaviour "highly ungrateful" in light of the measures Russia has taken in Syria to accommodate Israeli demands, including, he said, relocating Iranian troops from the border of the Israeli-occupied Golan Heights and providing Russian patrols in the area.

Israel responded with a statement disputing the Russian findings, saying that it had already presented Russia with a detailed account of the incident that demonstrated that Israel had acted within the boundaries of Russian-Israeli agreements.

Israel also claimed last week that its jets had returned to Israeli airspace when the missiles were launched.

Reuters, Washington Post