The government of Turkey has responded with ire to the news that the Trump administration would supply heavy arms to the Syrian Kurdish People’s Protection Units (YPG/YPJ), calling the move “unacceptable” and demanding the White House “put a stop to this wrong.”

The YPG are considered among the most successful militias fighting the Islamic State today, and Washington considers their work pivotal to eradicating the terrorist group. Ankara, however, sees the YPG as an arm of the Kurdistan Workers’ Party (PKK) a Marxist, U.S.-designated terrorist organization that Turkey fears is attempting to carve an independent Kurdistan out of Syrian and Turkish territory.

“Any initiative to support the PKK directly or indirectly is unacceptable for us,” Prime Minister Binali Yildirim said on Tuesday. “If the decision is negative, the outcome is not [only] up to Turkey but will negatively affect the U.S. too.”

Deputy Prime Minister Nurettin Canikli echoed this sentiment, calling the move “unacceptable.” “We cannot accept the presence of terrorist organizations that would threaten the future of the Turkish state. We hope the U.S. administration will put a stop to this wrong and turn back away from it. Such a policy will not be beneficial, you can’t be in the same sack as terrorist organizations,” Canikli said in an interview.

“The Trump administration providing arms to a terrorist organization — either directly or indirectly through the YPG — does not change the fact that this amounts to support to a terror organization,” Canikli added.

Foreign Minister Mevlüt Çavuşoğlu asserted on Wednesday that “Every weapon seized by [the YPG] is a threat to Turkey” because the YPG often shares weapons with the YPG, according to the Turkish government. “Both the PKK and YPG are terrorist organizations and they are no different apart from their names.”

The Pentagon announced on Tuesday that it would initiate a program to arm “Kurdish elements of the Syrian Democratic Forces,” a coalition militia largely consisting of YPG/YPJ but also including some Arab forces. The move, spokeswoman Dana White said in a statement, was “necessary to ensure a clear victory over ISIS in Raqqa, Syria.”

“The SDF, partnered with enabling support from U.S. and coalition forces, are the only force on the ground that can successfully seize Raqqa in the near future,” White added. The statement acknowledged Turkey’s concern. American troops have cooperated with the SDF and the YPG specifically for years, with the YPG providing on-the-ground intelligence that American soldiers have used to conduct airstrikes against the Islamic State. The YPG has a similar relationship with Russia.

Reports indicate that Defense Secretary James Mattis approved the move following a request from U.S. Central Command. Mattis spoke to Turkish Defense Minister Fikri Isik on Tuesday following the announcement, and told reporters that America’s “intent is to work with the Turks, alongside one another, to take Raqqah down, and we’re going to sort it out and we’ll figure out how we’re going to do it.”

“That’s not to say we all walk into the room with exactly the same appreciation of the problem or the path forward,” he warned.

Syrian Kurds and their supporters have long contended that the Trump administration was willing to anger Turkey to support them, however. “There are signs of full support from the new American leadership – more than before – for our forces,” SDF spokesman Talal Silo said of the Trump administration February.

SDF official Ilham Ahmed accepted the American decision on Tuesday, noting it “legitimizes the YPG and the Syrian Democratic Forces.”

In addition to this recent announcement, American soldiers have increased their presence on the Turkish-Syrian border following reports that Turkish soldiers were attacking the YPG/YPJ on its border, as the United States has not ceased in supporting that militia.

Turkish officials’ disapproval of American ties to the YPG will likely be a major topic of conversation on May 16, when President Recep Tayyip Erdogan is scheduled to meet President Donald Trump in Washington, their first in-person meeting.

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