A Turkish news agency provided a map and details of U.S.-run military outposts in northern Syria, prompting the Pentagon to say Wednesday it had relayed “concerns” about the article to Ankara.

“The release of sensitive military information exposes coalition forces to unnecessary risk and has the potential to disrupt ongoing operations to defeat ISIS, said Army Maj. Josh Jacques, a U.S. military spokesman, using an acronym for the terrorist group called the Islamic State.

The article, published by the state-run Anadolu Agency on Tuesday, included a map showing 10 U.S. bases spread across the part of northern Syria controlled mostly by Kurdish forces. The text of the piece included specific breakdowns of each base, including troop numbers and the location of possible French Special Operations forces. The Daily Beast first reported U.S. concerns about the article.

The incident marks the latest strain on the long-standing U.S.-Turkish relationship. Jacques said concerns about the map and accompanying report had been relayed through the State Department to Ankara. As of Wednesday afternoon, portions of the article appeared to have been removed.

Turkey, an American ally since the Cold War and a member of NATO, has been at odds with the United States for months as Washington has continued to lean on, and more recently arm, Kurdish fighters, known as the People’s Protection Units (YPG) to help push the Islamic State out of northern Syria. The Pentagon sees the Kurds as an integral partner in Syria, while Turkey views the YPG as an extension of the Kurdistan Worker’s Party, a U.S.-recognized terrorist group that has waged an insurgency against Ankara for years.

Levent Tok, an Anadolu Agency reporter who worked on the story, told Bloomberg News that the information had been compiled by field work and social media images. Open source information on U.S. military operations in Syria is often spotty, with most of the information coming from publicly available satellite imagery and videos posted by combatants on the ground.

It is unclear how many U.S. troops are in Syria. The last official count by the Pentagon put the number at around 500, but other sources suggest the number is closer to 1,500. U.S. troops are in the country helping Syrian fighters battle the Islamic State while running a number of key airfields and installations in support of those operations.

Read more: