Turkish President Recep Tayyip Erdogan once again attempted to convince his American counterpart, President Donald Trump, to allow Turkey to control Manbij, a region in northern Syria under the auspices of the Syrian Kurdish People’s Protection Units (YPG/YPJ), in a phone call Sunday.

The YPG is one of America’s closest and most reliable allies in the country, responsible for eliminating much of the Islamic State presence in Syria and keeping the terrorist group out of Manbij and much of Syrian Kurdistan (Rojava). The Turkish government considers YPG fighters “terrorists” indistinguishable from the Kurdistan Workers’ Party (PKK), a Marxist, U.S.-designated terrorist group.

Trump and Erdogan reportedly spoke late Sunday on the situation in Syria, which deteriorated last week with a bomb killing four American soldiers at a restaurant in Manbij, an attack claimed by the Islamic State. Erdogan, according to the Turkish presidential office, told Trump that Turkish troops could occupy Manbij and eradicate the YPG from there immediately. Trump had announced in December his intention to withdraw troops from Syria completely as soon as possible because, in his estimation, the Islamic State no longer posed a threat.

The Turkish newspaper Hurriyet translated the Ankara message on the call as being that Turkish soldiers could immediately fill any void that U.S. troops left in northern Syria. “A statement from the Turkish presidency said Erdoğan and U.S. President Donald Trump agreed to take joint measures to clear ISIL’s [ISIS’s] remnants in Syria and prevent the group’s resurgence,” the newspaper related.

The White House statement did not address one way or another if President Trump was considering withdrawing from Manbij and fully replacing the U.S. presence with Turkish troops. Instead, White House Press Secretary Sarah Sanders said that Erdogan used the call to express “condolences for the tragic loss of American lives in Manbij, Syria this week” and that both presidents “agreed to continue to pursue a negotiated solution for northeast Syria that achieves our respective security concerns.”

Trump initially did not specify what the fate of the U.S.-YPG partnership would be following the withdrawal of American troops from the region, instead insisting that the only legitimate reason for American troops to be in Syria was to destroy the Islamic State, a defecting branch of al-Qaeda. The Turkish government immediately seized on the opportunity in December to volunteer itself to eradicate the YPG from Manbij in the event that American troops would leave the area, as Turkey had spent months lobbying the U.S. to allow them to attack the militia primarily responsible for defeating the Islamic State in its “capital,” Raqqa, with partial success – the YPG and U.S. troops withdrew from Afrin, another city in northern Syria.

Turkish troops postponed any action against the YPG until they could coordinate with Washington.

This month, while visiting Israel, National Security Editor John Bolton insisted that American troops would not abandon their Syrian Kurdish allies, prompting Erdogan to refuse to meet with him in Ankara. Trump echoed Bolton’s remarks shortly after that incident, however, stating on Twitter that the United States would “devastate Turkey economically if they hit Kurds.”

Erdogan subsequently claimed that Trump had offered Turkey the chance to establish a “safe zone” in Manbij, which the Kurdish leadership there enthusiastically rejected given Erdogan’s repeated threats to annihilate them.

“Mr. Trump once again confirmed his decision to withdraw from Syria. He also spoke about a security zone more than 30 kilometers [about 18 miles] deep inside [Syria], which would be set up by us, an issue that I had raised during the Obama administration,” Erdogan claimed.

On Monday, Erdogan once against attempted to argue that a Kurdish presence in Kurdish Syria, and thus on the border with Turkey, was unacceptable to him.

“We can never allow an implementation of a safe zone [to be established in northern Syria] to be transformed into another swamp against our country,” he told the Turkish Union of Chambers and Commodity Exchanges (TOBB), where he was scheduled to deliver remarks. “We will never allow the formation of a safe zone that will be turned into a new ground for terrorists.”

He added that he hoped negotiations with the United States and other prominent actors in the region like Russia would result in Turkish control of the area, or “a common understanding.” Erdogan is scheduled to visit Moscow and meet with Russian President Vladimir Putin on Wednesday.

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