Kurdish fighters from the People's Protection Units (YPG) fire at a drone operated by Islamic State militants in Raqqa, Syria, in June. (Goran Tomasevic/Reuters)

The Trump administration has backed away from its description of a planned security force in northeastern Syria amid escalating threats by Turkey to launch a cross-border assault against the Kurdish group involved.

But Turkish Foreign Minister Mevlut Cavusoglu said Thursday the new language being used to describe what was originally billed as a border security force did not assuage Turkey's concerns about the United States' relationship with the Syrian Kurds.

Turkey is pressing ahead with plans to launch a military operation in Syria, he told CNN Turk, and has dispatched its military chief of staff, Hulusi Akar, to Moscow to secure Russian consent. Russia controls the skies over the area that Turkey is preparing to attack and could potentially down Turkish planes.

Syria, however, warned Thursday that it was prepared to shoot down Turkish planes if Turkish troops attack the Kurdish enclave of Afrin, on the Syrian border with Turkey, underscoring the risk of a wider regional conflict.

"The Syrian air defenses have restored their full force, and they are ready to destroy Turkish aviation targets in Syrian Arab Republic skies," Syria's deputy foreign minister, Faisal Mekdad, said in a statement published by state media.

Any such war also risks embroiling the United States, which is closely allied with the Syrian Kurds and Turkey, and frequently finds itself caught between the two. The confusion over the purported border force appears to stem in part from a lack of coordination in Washington between the different branches of the administration involved in the war against the Islamic State, said Nicholas Heras of the Washington-based Center for a New American Security.

"The Afrin crisis shows how difficult it is for U.S. policymakers to walk and chew gum when it comes to Syria," he said. "This is shoot-from-the-hip policymaking."

In this instance, U.S. military officials drew Turkey's ire over the weekend by announcing that they were training a "border security force" to guard the perimeter of a separate self-proclaimed Kurdish enclave taking shape along Turkey's border farther to the east.

Such a force also would effectively cement the emerging status of the Kurdish-led entity, which is modeled on the vision of Abdullah Ocalan, a Kurdish leader jailed for terrorism in Turkey.

Ocalan heads the Kurdistan Workers' Party, or PKK, which is fighting a guerrilla insurgency against Turkey and is closely allied with the Kurdish People's Protection Units, or YPG, in Syria. The YPG, in turn, is the lead component of the U.S.-backed Syrian Democratic Forces (SDF), which was created in 2015 to fight the Islamic State and now controls northeastern Syria.

The United States maintains around 2,000 troops in the area, where they have been training and advising SDF fighters.

Reports of the planned new force provoked an outcry in Turkey, whose leaders have long accused the United States of enabling terrorism by supporting the Kurds in Syria. Iran also has expressed displeasure, and on Thursday the Syrian government said it would exert all of its efforts to end what it called the "illegitimate" U.S. presence in Syria, according to the state-run Syrian Arab News Agency.

Turkey, meanwhile, has dispatched tanks and troops to the Syrian border, where they appear poised to launch an attack on another Kurdish-controlled enclave outside the area where the United States maintains troops.

Confronted with the prospect of an imminent war that could draw in the United States and force Washington to choose between two important allies, U.S. officials have been hastily recalibrating their descriptions of the force.

The force "was not properly described," Secretary of State Rex Tillerson told reporters Wednesday after meeting with Cavusoglu in Vancouver, B.C.

"It's unfortunate that entire situation has been misportrayed, misdescribed; some people misspoke," he said. "We are not creating a border security force at all."

Rather, he said, the U.S. military will provide training to local elements to help secure areas that were liberated from the Islamic State, with U.S. assistance, over the past three years.

The U.S. military said in a statement emailed to journalists that the force would be "internally focused."

"This is not a new 'army' or conventional 'border guard' force," the statement said. "These security forces are internally-focused to prevent Daesh fighters from fleeing Syria. These forces will augment local security in liberated areas and protect local populations." Daesh is an Arabic acronym for the Islamic State.

The United States is "keenly aware of the legitimate security concerns of Turkey, a member of the Global Coalition and a NATO ally," the statement added.

But Cavusoglu said in his interview with CNN Turk that "the U.S. declarations do not entirely satisfy us. . . . Our mistrust toward the United States continues."

Read more: