ISTANBUL (Reuters) - Turkish Prime Minister Ahmet Davutoglu said Turkey had struck Kurdish militia fighters in Syria twice after they defied Ankara's warning not to cross west of the Euphrates river.
Ankara fears that advances by the Kurdish YPG militia, backed by its PYD political wing, on the Syrian side of its 900 km (560-mile) border will fuel separatist ambitions among Turkey's own Kurds in the southeast of the country.
Washington has supported Kurds in Syria as an effective force in combating Islamic State militants, complicating its relationship with longtime ally and fellow NATO member Turkey.
"We have said 'PYD will not cross west of the Euphrates, we will hit them the moment they do' and we have struck them twice," Davutoglu told AHaber Television late on Monday, without saying when the incidents took place.
Two senior Turkish officials told Reuters that Ankara had warned the United States and Russia earlier this month that it would not tolerate Kurdish militias encroaching on territory in northwestern Syria close to its border.
The YPG militia said in statements over the weekend that the Turkish army had twice attacked its positions near the border towns of Tel Abyad and Kobani.
"Turkey has drawn its red line as the west of Euphrates and this incident is in line with that warning," a Turkish government official told Reuters, also without specifying a date for the incident.
Tel Abyad, on the border with Turkey, was captured in June from Islamic State by Kurdish YPG militia backed up by U.S.-led air strikes. Last week a local leadership council declared it part of the system of autonomous self-government established by the Kurds.
That has infuriated Turkish President Tayyip Erdogan, who on Saturday accused Kurdish groups of trying to grab control of all of northern Syria, adding that Ankara would not allow that to happen.
Syrian Kurds have established three autonomous zones, or "cantons", across northern Syria since the civil war broke out in 2011. They deny aiming to establish their own state.
Additional reporting by Sylvia Westall in BEIRUT; Editing by David Dolan and Gareth Jones