ANKARA (Reuters) - The United States has told Turkey it will not provide any more weapons to the Syrian Kurdish YPG militia, the Turkish presidency said on Saturday, as Turkey’s offensive against the U.S.-backed YPG in Syria entered its eighth day.

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The Turkish incursion in northwest Syria’s Afrin region against the YPG has opened a new front in the multi-sided Syrian civil war, but has also further strained ties with NATO ally Washington.

Washington has angered Ankara by providing arms, training and air support to the Syrian Kurdish forces. Turkey sees the YPG as an extension of the outlawed Kurdistan Workers Party (PKK), which has waged a deadly insurgency in Turkey’s largely Kurdish southeast for three decades.

The Turkish presidency said in a statement on Saturday that Ibrahim Kalin, spokesman for President Tayyip Erdogan, and U.S. National Security Adviser H.R. McMaster held a phone call on Friday in which McMaster confirmed the United States would no longer provide weapons to the YPG.

On Thursday, the Pentagon said it carefully tracked weapons provided to the YPG and would continue discussions with Turkey, after Ankara urged Washington to end its support for the YPG or risk confronting Turkish forces on the ground in Syria.

On Friday, Erdogan said Turkish forces would sweep Kurdish fighters from the Syrian border and could push all the way east to the frontier with Iraq - a move which risks a possible confrontation with U.S. forces allied to the Kurds.

Since the start of the incursion, dubbed “Operation Olive Branch” by Ankara, Erdogan has said Turkish forces would push east towards the town of Manbij, part of Kurdish-held territory some 100 km (60 miles) east of Afrin, where U.S. troops were deployed to deter Turkish and U.S.-backed rebels from clashing.

Any Turkish advance towards Manbij could threaten U.S. efforts to stabilize northern Syria, where the United States has about 2,000 troops, officially as part of the international coalition against Islamic State.

In a sign of growing bilateral tensions, Ankara and Washington disagreed over the main message of a phone call between Erdogan and U.S. President Donald Trump held on Wednesday.

The White House said Trump had urged Erdogan to curtail the military operation in Syria, while Turkey said Erdogan had told Trump that U.S. troops should withdraw from Manbij.

Pentagon spokeswoman Dana White said she had seen media reports about the phone call, but was not aware of any change in U.S. posture.

The Turkish presidency said Kalin and McMaster had agreed for Turkey and the United States to remain in close coordination to “avoid misunderstandings”.