"The United States will not give any military support [to Turkey]," the official said on Thursday. "It was asked by the Turks at various levels at various times, including on the call [between US President Donald Trump and Turkish President Recep Tayyip Erdogan] on Sunday. That was made clear to the Turks."

The official added that the United States will not oppose Turkey's invasion with military force, but it will do its best to stop it.

The incursion endangers US partners in the fight against the Islamic State (banned in Russia) terrorist group such as the Syrian Democratic Forces, the official said. The official emphasized that the operation creates a tremendous security risk for the entire region.

Operation Peace Spring was launched on Wednesday and is aimed at creating the so-called safe zone near the Syrian-Turkish border. The territory on the Syrian side of the border is currently controlled by the Kurdish-led Syrian Democratic Forces (SDF), which Ankara believes are affiliated with the PKK, just like the YPG.

The Syrian government has condemned the Turkish offensive in northern Syria as an act of aggression, and this sentiment has since been echoed by Russia, and a number of Arab and Western nations.

According to the Turkish Defense Ministry, since the beginning of Operation Peace Spring Turkey's military has neutralized 219 members of the PKK-YPG.