As clashes continue between NATO ally Turkey and Kurdish militant group the People's Protection Unit, U.S. forces are patrolling the border region in an operation reminiscent of the "reassure and deter mission" launched in Syria in March.

In that case, U.S. Army Rangers were sent to the Syrian city of Manbij to deter Turkish aggression against the United States' Kurdish allies in the fight against ISIS.

"We have forces in the entirety of northern Syria, the border is among the area where they operate," said Navy Capt. Jeff Davis, a Pentagon spokesman. 

Officials at the Pentagon would not confirm whether forces had been dispatched to the border region specifically to deter fighting between Turkish and People's Protection Unit, or YPG, forces. However, pictures online appear to show U.S. armored vehicles displaying the American flag — a tactic used by the Rangers in Manbij to highlight American forces' visible presence in the region.

Moreover, a Syrian YPG commander on Friday told Reutersthat U.S. forces would soon be monitoring the situation along the Syria-Turkey border.

Clashes between Turkish and YPG forces have intensifiedover the last several days, after Turkey launched deadly airstrikes against Kurdish militant positions in northern Syria and Sinjar, Iraq. The strikes killed a number of YPG and peshmerga forces — forces that are assisting the U.S. in its fight against ISIS.

This Tuesday, March 7, 2017 frame grab from video provided by Arab 24 network, shows U.S. forces take up positions on the outskirts of the Syrian town, Manbij, a flashpoint between Turkish troops and allied Syrian fighters and U.S.-backed Kurdish fighters, in al-Asaliyah village, Aleppo province, Syria. Syrian government forces backed by Russia also operate in the area. The U.S. military's new mission,
This Tuesday, March 7, 2017 frame grab from video provided by Arab 24 network, shows U.S. forces take up positions on the outskirts of the Syrian town, Manbij, a flashpoint between Turkish troops and allied Syrian fighters and U.S.-backed Kurdish fighters, in al-Asaliyah village, Aleppo province, Syria. Syrian government forces backed by Russia also operate in the area. The U.S. military's new mission, "reassure and deter," is designed to prevent the Syria conflict from escalating through confrontation between the Turkish troops and the rival Syrian Kurdish forces. (Arab 24 network, via AP)

U.S. forces take up positions on the outskirts of the Syrian town, Manbij, a flashpoint between Turkish troops and allied Syrian fighters and U.S.-backed Kurdish fighters, in al-Asaliyah village, Aleppo province, Syria, on March 7. Syrian government forces backed by Russia also operate in the area.

Photo Credit: Arab 24 network via AP

Ankara views the YPG as the Syrian branch of the PKK, a group designated as a terrorist group by both the U.S. and Turkey. However, U.S. military officials have come to rely on the potent and capable Kurdish faction in its war against ISIS.

The escalation of force between Ankara and the YPG  could complicate the operation to liberate Raqqa, the ISIS capital in Syria.

On Wednesday, YPG spokeswoman Nesrin Abdullah lashed out at the lack of a U.S. response to Turkey’s aggression.

"Our people are expecting a response from us on why the coalition is not showing Turkey a concrete reaction. If the coalition does not show a concrete reaction, then we will withdraw our forces from Raqqa," she told a local Kurdish news outlet.

The operation to liberate Raqqa is still ongoing, according to Davis. Syrian Democratic Forces (SDF), alongside the Syrian Arab Coalition (SAC), are continuing to isolate Raqqa for its impending liberation from ISIS.

The city of Tabqa, the last remaining obstacle to completely surrounding Raqqa, is almost completely encircled, Davis said.

Meanwhile, Turkish President Recep Tayyip Erdogan is set to visit the White House in the coming weeks, and the strain between Washington and Ankara over the YPG likely will be a topic of discussion.