A picture of a U.S. soldier withdrawing from Syria sporting a patch of a controversial Kurdish militia group known as the YPJ has been making the rounds across social media.

The YPJ is the women’s unit of the YPG, or People’s Protection Units — the Kurdish group considered a terrorist organization by Turkey, but has been a staunch partner of the U.S.-led effort to defeat ISIS in Syria.

It’s common for U.S. special operators to don patches of partner forces. But in 2016, American military commanders banned the wear of YPG and YPJ patches after Turkey became outraged following the circulation of photos of American commandos brandishing the patches.

“Wearing those YPG patches was unauthorized, and it was inappropriate and corrective action has been taken,” then-Army Col. Steve Warren, a Baghdad-based spokesman, told reporters in May 2016. “And we have communicated as much to our military partners and our military allies in the region.”

Neither officials with Operation Inherent Resolve — the U.S.-led mission to defeat ISIS in Iraq and Syria — nor officials with the Department of Defense responded to a Military Times’ query regarding whether the YPG/YPJ patches were still unauthorized.

As American convoys began to meander their way through Syria on Sunday, Agence France-Presse photographer Delil Souleiman snapped a photograph of a U.S. service member in the turret of an armored vehicle wearing the YPJ patch.

Commentators on social media quickly remarked that the U.S. soldier was showing solidarity or camaraderie with the U.S.-backed Kurdish partner force.

President Donald Trump ordered the withdrawal of roughly 1,000 U.S troops from northern Syria shortly after Turkey launched a military operation to rout America’s Kurdish partner force in the region.

Trump’s decision to pull out American forces has left its partner force the Syrian Democratic Forces feeling betrayed. American troops and U.S. veterans who volunteered and fought with the SDF have expressed their dismay over the decision.

Secretary of Defense Mark Esper told reporters Saturday that the withdrawal of U.S. forces from Syria could take weeks, not days. Those forces will relocate to western Iraq where they will continue the defeat ISIS mission.

A small handful of American troops will remain at the Tanf garrison near the Syria-Iraq border.