WASHINGTON — According to Kurdish activists in northern Syria, U.S. special operations forces were recently dispatched to the Kurdish-controlled city of Tal Abyad, near the Syria-Turkey border, as tensions flare in the fight against ISIS.

Officials in Baghdad would not confirm or deny the reports, citing operational security.

"Coalition special forces advise, assist and accompany partner forces wherever they are needed to defeat ISIS in Syria," said a spokesperson at U.S. Central Command. 

Over the past week, the Turkish military has steadily built up forces in northern Syria outside of the district of Afrin, which has been controlled by the Kurdish People’s Protection Units, or YPG — a group Ankara calls a terrorist organization.

According to the Syrian Observatory for Human Rights and a spokesperson for the YPG, there has been shelling along the Syria-Turkey border over the past five days by Turkey and its Free Syrian Army proxy force.

Cross-border skirmishes and indirect fire between Kurdish and Turkish-supported forces are common across the border region, officials at CENTCOM confirmed last week.

The arrival of U.S. special operations forces to the Kurdish-controlled city is reminiscent of "observe and report" missions that were carried out by U.S. Army Rangers along the border region in northern Syria last April. Those were after Turkish warplanes attacked YPG and Iraqi Peshmerga positions in northern Syrian and Iraq, killing several U.S. partnered forces.

However, U.S. special operations forces in Tal Abyad can be seen in videos posted to social media driving in technicals — a modified pickup truck with a mounted machine gun. The vehicle also has an American flag and satellite communications antenna mounted on the roof.

As U.S. forces arrived in the city to visit checkpoints, the Kurdish fighters can be heard in the video saying, "Turkey forces want to enter the area."

The city of Tal Abyad is strategic to Turkey and the Kurds, one YPG volunteer told Military Times.

"It’s a waypoint between the major cities of Kobanê and Qamishli," he said. Turkey may be interested in severing that link.

Analysts believe an attack by Turkey against YPG positions in northern Syria could disrupt operations in Raqqa, where Kurdish-led forces are in their third week of operations to liberate it from ISIS.

"An attack (in the vicinity of) Afrin could piss off the YPG enough to disrupt the Raqqa operation, but I think a mediation and de-escalation there is more likely," said Jennifer Cafarella, a Syrian civil war expert at the Institute for the Study of War, a Washington think tank.

So far, there have been no signs that YPG commanders or fighters plan to re-deploy from Raqqa to northern Syria as a result of the increasing hostilities between Ankara and the Kurds, according to a spokesperson at U.S. Central Command.

But, the presence of U.S. special operations forces in Tal Abyad after Turkey threatened the city is a sign that Washington is taking the Turkish provocations seriously.

Relations between Ankara and Washington have been fretful since the Trump admoinistrration decided in early May to arm the Kurdish militants in a push to liberate Raqqa.

Officials in Baghdad contend the weapons supplied to the Kurdish fighters will be tracked and metered out, and eventually taken back by the U.S.

But Turkish President Tayyip Erdogan did not buy into the U.S.’ pledge.

"The ones who think they are tricking Turkey by saying they are going to get back the weapons that are being given to this terrorist organization will realize that they are making a mistake eventually," he said, as reported by Reuters.

On Tuesday, U.S. Defense Secretary James Mattis said the U.S. will continue to provide weapons to the Kurds after the fall of Raqqa, according to AP. The next stepping stone for the U.S. and its Kurdish allies in Syria is likely the Euphrates River valley. Nearly 5,000 to 10,000 ISIS fighters occupy the area, according to a spokesperson at CENTCOM.