By SUZAN FRASER and JAMEY KEATEN
Associated Press

ANKARA, Turkey (AP) - The United States would prefer that Turkish troops "remove themselves" from a conflict in the Syrian border town of Afrin and focus on "long-term strategic goals" like ending Syria's war, President Donald Trump's homeland security adviser said Thursday.

Speaking at the World Economic Forum in Davos before Trump's arrival, Tom Bossert said Turkey "ought to be mindful of the potential for escalation as they move into Syria and Afrin."

The United States has expressed concerns over Turkey's military offensive against the Kurdish-controlled enclave of Afrin in northwestern Syria, which began Saturday, but Bossert's comments were the most direct call yet for Turkey to withdraw.

Turkey has vowed to expand its operation against Syrian Kurdish forces, known as the People's Defense Units or YPG, to other areas along the border. Ankara views the YPG as a major threat because of its links to Kurdish insurgents in Turkey.

The YPG forms the backbone of the Syrian Democratic Forces, a U.S. ally that drove the Islamic State group from much of northeastern Syria. U.S. troops are embedded with the SDF in other parts of Syria, where they are working to prevent a resurgence of IS, but do not operate in or near Afrin.

The rising tensions between the U.S. and its NATO ally Turkey were on display after a phone call Wednesday between Trump and his Turkish counterpart, Recep Tayyip Erdogan.

The White House said Trump expressed concern about the fighting and told Erdogan the Afrin operation jeopardizes shared goals in Syria. It said Trump also expressed concern about "destructive and false rhetoric coming from Turkey," in reference to recent anti-American statements made by Turkish officials.

Turkish officials disputed the White House readout, saying it did not "accurately reflect" the content of their discussions. They said Trump did not voice concerns about the violence or use the phrase "destructive and false rhetoric coming from Turkey." The officials spoke on condition of anonymity in line with government rules.

Turkish Prime Minister Binali Yildirim lashed out at the United States, saying "it is astounding and unacceptable ... that a country which is supposed to protect NATO's borders is giving open support to armed entities that target our borders."

Turkish Foreign Minister Mevlut Cavusoglu told reporters that U.S. Secretary of State Rex Tillerson, during a meeting in Paris this week, had raised the possibility of the creation of a 30-kilometer-deep (20-mile) "safe zone" in Syria running along Turkey's border. But he said trust between Ankara and Washington has to be restored before Turkey would be prepared to discuss the issue. When asked in Davos about the safe zone, Tillerson said "we discussed a number of possible options but we didn't propose anything."

Bossert meanwhile said it would be a "terrible outcome" if Turkish troops clashed with "the proxy forces that we have all been relying on to defeat ISIS, especially if there are U.S. advisers in the region." He said there could be "grave consequences to any miscalculation and escalation."

He acknowledged Turkey's "legitimate security concerns" about the Syrian Kurdish forces along its border, but said they were "smaller concerns than the grander strategic need for a stable and supportable Syria."

"I'm not in any way critical of the Turkish decisions, but I'm just praying for their longer-term strategic patience," Bossert said.

A new round of U.N.-led talks on Syria opened Thursday in Vienna, where U.N. special envoy Staffan de Mistura met with Syrian government representatives and planned to separately hold talks with an opposition delegation.

De Mistura said the talks, which have made little if any progress since they began four years ago, are at a "very critical moment." Russia plans to hold separate peace talks on Jan 29.

Islamic State militants meanwhile launched a wave of attacks against government forces in eastern and northern Syria. The extremists have been driven from nearly all the territory they once held in Syria and neighboring Iraq but have proved they can still carry out insurgent-style attacks.

The Syrian Observatory for Human Rights said IS militants attacked Syrian troops and allied forces stationed in the eastern Deir el-Zour province, killing over a dozen fighters in attacks several kilometers (miles) apart.

State media also reported the attack, saying it had been repelled. IS announced a new offensive against Syrian government forces on its social media accounts.

The Observatory said the militants are also on the offensive in northern Syria, where they seized a number of villages in Aleppo province that position them closer to a strategic road linking northern and central Syria.

Over the past month, IS has established a presence in the northwestern Idlib province for the first time in four years, after it was expelled by rival Syrian insurgent groups.

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Keaten reported from Davos, Switzerland. Associated Press writer Sarah El Deeb in Beirut contributed.

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