ISTANBUL, TURKEY - Turkish Vice President Fuat Oktay is warning the United States of the danger of a rupture in relations, as myriad differences between the two NATO allies escalate tensions.

"The United States must choose. Does it want to remain Turkey's ally or risk our friendship by joining forces with terrorists to undermine its NATO ally's defense against its enemies?" Oktay tweeted Thursday.

The tweet follows a warning to Ankara from Secretary of State Mike Pompeo not to militarily intervene against the YPG, a Syrian Kurdish militia, in northern Syria. The militia is a crucial U.S. ally in the war against the Islamic State terror group, but Ankara designates the YPG a terrorist organization linked to an insurgency inside Turkey.

“Secretary Pompeo expressed support for ongoing negotiations regarding northeast Syria while warning of the potentially devastating consequences of unilateral Turkish military action in the region,” the State Department said in a statement after Pompeo met with visiting Turkish Foreign Minister Mevlut Cavusoglu Wednesday.

U.S. Secretary of State Mike Pompeo, right, meets U.S. Secretary of State Mike Pompeo, right, meets with Turkish Foreign Minister Mevlut Cavusoglu at the U.S. Department of State in Washington, April 3, 2019. U.S. Secretary of State Mike Pompeo, right, meets with Turkish Foreign Minister Mevlut Cavusoglu at the U.S. Department of State in Washington, April 3, 2019.

Cavusoglu highlighted what he called the lack of "clear strategy" in Washington over Syria.

Turkish President Recep Tayyip Erdogan, reeling from the loss of several key cities in local elections this past Sunday, has declared security a priority, a comment interpreted by some as code for a possible military incursion into Syria against the YPG. Turkish forces remain massed on the Syrian border.

The threat of a showdown over Syria comes amid a growing disagreement between Washington and Ankara over Turkey’s procurement of Russia’s S-400 missile system. U.S. officials say the missiles will compromise NATO weapons systems.

"Turkey must choose. Does it want to remain a critical partner in the most successful military alliance in history, or does it want to risk the security of that partnership by making such reckless decisions that undermine our alliance?" U.S. Vice President Mike Pence said in comments at a Wednesday NATO event in Washington.

Vice President Mike Pence addresses the Atlantic C Vice President Mike Pence addresses the Atlantic Council's "NATO Engages The Alliance at 70" conference, in Washington, April 3, 2019. Vice President Mike Pence addresses the Atlantic Council's "NATO Engages The Alliance at 70" conference, in Washington, April 3, 2019.

"The purchase from Russia is a done deal," Cavusoglu said at an earlier NATO panel. "We are not choosing between Russia and any other allies. We don't see our relations with Russia as an alternative to our relations with others. Moreover, nobody, neither the West nor Russia, should or can ask us to choose," he added.

Washington is offering Turkey a Patriot missile system. Ankara has indicated a willingness to buy the system but not as an alternative to the Russian S-400s.

The dispute is part of broader concerns among Turkey’s Western allies over Erdogan’s deepening relationship with Russian President Vladimir Putin. Next week, Erdogan is set to visit Moscow where Putin is expected to seek to bolster Turkey’s resolve to buy Russia's S-400s. Russia is set to deliver the missiles in the second half of this year.

Russian servicemen drive S-400 missile air defence FILE - Russian S-400 missile air defense systems are on display during a parade at Red Square in Moscow, Russia, May 9, 2018. FILE - Russian S-400 missile air defense systems are on display during a parade at Red Square in Moscow, Russia, May 9, 2018.

Washington is warning the delivery of its latest F-35 warplanes to Turkey is at risk with the delivery of the S-400s.

”There's great opportunities for the United States and Turkey to work closer together," Pompeo told reporters Thursday during a news conference at the end of a meeting of NATO foreign ministers. "I had a good long conversation with the Turkish foreign minister yesterday and I'm very confident we'll find a path forward."

Analysts say further measures against Turkey are now looming and that the currency, the lira, could ultimately be the most significant casualty of any U.S.-Turkish showdown.



Analysts say the lira is vulnerable, following last year’s collapse triggered by U.S. President Donald Trump hitting Ankara with sanctions over the detention in Turkey of American pastor Andrew Brunson, who has since been released.

“This climb-up has all the makings of last year’s 'Father Brunson’ crisis. We doubt history repeats only for those who refuse to learn from it,” said Atilla Yesilada of Global Source Partners.

Growing financial concerns about the Turkish economy saw Turkey’s Central Bank forced to use unprecedented measures to support the currency earlier this month to quell heavy lira falls. The currency declines were triggered by local Turks converting savings to foreign currency, along with international investors exiting the market amid economic concerns.

A street vendor sells banners with a photo of Turk FILE - A street vendor sells banners with a photo of Turkish President Tayyip Erdogan in Uskudar district in Istanbul, Turkey, July 21, 2016. FILE - A street vendor sells banners with a photo of Turkish President Tayyip Erdogan in Uskudar district in Istanbul, Turkey, July 21, 2016.

Despite the high economic stakes, however, analysts warn it will be difficult for either side to back down.

“It's part of a much wider rift in terms of U.S.-Turkish relations,” said Sinan Ulgen of the Istanbul-based Edam research institution.

“This would have never have happened if there had not been a vast erosion of trust between the two NATO allies, triggered by a number and ongoing disputes,” Ulgen said.

In a sign of Washington’s patience running out with Ankara, a new crisis could be looming. During Wednesday’s talks with his Turkish counterpart, Pompeo called for "the swift resolution of cases involving unjustly detained U.S. citizens, including Serkan Golge, as well as our local staff from the U.S. Mission in Turkey," said a State Department readout of the meeting.

Golge, along with three local diplomatic employees, are jailed on accusations of links to terrorist organizations including conspirators blamed by Ankara for a failed 2016 coup.

Until now, Washington has sought to use behind-the-scenes diplomacy to resolve the dispute. Observers suggest Pompeo's public statement indicates the adoption of a more confrontational strategy.

Some analysts say Ankara’s steadfastness against growing Washington pressure stems from a belief that Trump does share concerns over Turkey.

"Ankara is still not convinced that Washington is serious in its threats," Yesilada said. “More specifically, it suspects, as transpired several times in the past, the threats and warnings don’t reflect Trump’s viewpoint,” he said.