Turkish President Recep Tayyip Erdogan said on Monday that an attack that Ankara blamed on the U.S.-backed YPG that killed two Turkish police was “the final straw” and that Turkey was determined to eliminate threats originating in north Syria.

Turkey said police in northern Syria’s Azaz region were hit in a guided missile attack on Sunday launched by the YPG, which Turkey says is a terrorist group.

On Monday, shells believed to have been fired from a YPG-controlled area further east exploded in two areas of Karkamis in southern Turkey, Ankara said.

Speaking at the news conference in Ankara, Cavusoglu said the United States and Russia had not kept their promises to ensure the YPG withdraw from the Syrian border area.

Both Russia and the United States have failed to keep their promises to Turkey in northern Syria, leaving Turkey to take action on its own, Cavusoglu said in the press event on Wednesday.

“As these terrorists are present there and have increased their attacks, what are we to do? Cut our own umbilical cord. We will do whatever is necessary to clear these regions of these terrorists,” Cavusoglu said.

The minister was referring to the parts of northern Syria covered by Turkey’s 2016 Operation Euphrates Shield, namely the area between the River Euphrates and the city of Azaz in the Aleppo province.

The United States was supposed to move “terrorists in this area at least 30 km to the south”, Cavusoglu said, while Russia was to clear Tel Rifat and Manbij, Cavusoglu said. “Russia and the United States share responsibility in attacks against civilians and us in this area,” he added.

Cavusoglu said the United States’ condemnation of attacks was “for show”.

“Who provides these weapons? Who trains these? You give weapons, you provide training, then you make a condemning statement, for show. The insincerity is clear here,” the minister said.

On Tuesday, U.S. State Department Spokesman Ned Price expressed condolences for Turkish police officers killed in an operation in Syria and called for a stop to cross-border attacks.

Turkey controls swathes of territory in north Syria with allied Syrian rebels, after carrying out three separate cross-border offensive into the region against Islamic State and the YPG. Ankara has been infuriated by the U.S. support for the YPG and demands its NATO ally ceases its backing.

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