Tillerson will meet Turkish Foreign Minister Mevlut Cavusoglu on Friday morning.

ANKARA, Feb 15, 2018 (AFP) - US Secretary of State Rex Tillerson on Thursday held talks with Turkish President Recep Tayyip Erdogan in Ankara, seeking to ease tensions between the NATO allies that reached new heights over Ankara s ongoing operation inside Syria.

A prime task of President Donald Trump s top diplomat will be to allay Turkish anger over US policy in Syria, a dispute which has ignited the biggest crisis in bilateral ties since the 2003 Iraq war.

The former chief of energy giant Exxon Mobil, who is on a multi-leg tour of the Middle East, met Erdogan at his presidential palace after landing in Ankara from Beirut.

Tillerson will meet Foreign Minister Mevlut Cavusoglu on Friday morning.

Turkey s operation against the People s Protection Units (YPG) Kurdish militia in the Afrin region of Syria has added a potentially insurmountable new problem to an increasingly rough bilateral relationship.

Analysts said the level of tension was similar to 2003 when Turkey refused to let US troops operate from its territory for the Iraq war, or even the aftermath of Ankara s invasion of Cyprus in 1974.

Turkey s operation against the YPG, which Ankara blacklists as a terror group, has seen Turkish troops fighting a militia which is closely allied with the US in the battle against Islamic State (IS) group jihadists.

Speaking in Beirut before his meeting with Erdogan, Tillerson denied Washington ever gave heavy weaponry to the YPG and thus could not gather up such arms, as desired by Ankara.

"We have never given heavy arms to the YPG so there is none to take back," Tillerson said.


Weakening anti-IS efforts

Erdogan earlier this month accused Washington of sending in thousands of truckloads and planeloads of weapons to the YPG in Syria, asking why the US still had a presence there if the jihadists had been defeated.

And Erdogan has further upped the ante by warning US troops to leave Manbij, a YPG-held town east of Afrin, raising fears of a clash between the allies.

He also warned that the US risked being dealt an "Ottoman slap" in Syria -- a backhand thwack which, according to legend, could kill an opponent at a stroke.

For Ankara, the YPG is a branch of the outlawed Kurdistan Workers  Party (PKK), which is blacklisted as a terror outfit by the US and the EU.

But for Washington, the YPG is an ally against IS jihadists and Turkey s operation is a distraction from efforts to ensure the Islamist extremists are permanently defeated.

But Cavusoglu this week warned Washington that ties were at a "critical point" at which relations would "be fixed or... completely damaged."

It was unclear whether Tillerson s visit could achieve any kind of breakthrough.

Following a meeting with US Defense Secretary Jim Mattis in Brussels, Turkish Defence Minister Nurettin Canikli said Ankara wanted to see the YPG pulled out of the Syrian Democratic Forces (SDF) umbrella group.

He said Mattis had promised greater support in Turkey s fight against the PKK in their rear bases in northern Iraq.


Litany of problems

The squabble over Syria is, however, just one of a litany of issues burdening Turkey-US relations.

Ties were damaged after the failed coup of 2016 with Turkey stung by a perceived lack of US solidarity and angered by Washington s refusal to extradite Fethullah Gulen, a Pennsylvania-based cleric blamed for ordering the putsch.

Last month, Ankara reacted furiously to the conviction in New York of Turkish banker Mehmet Hakan Atilla on charges of violating sanctions against Iran.

And Washington has expressed concern that several of its citizens -- as well as at least two Turkish employees of US missions -- have been caught up in the post-coup crackdown.

Last week, NASA scientist Serkan Golge, a dual national, was jailed for seven-and-a-half years for being a member of Gulen s movement, with the State Department saying he had been convicted "without credible evidence".

Another case is that of US pastor Andrew Brunson, who ran a church in Izmir, who has been held on similar charges since October 2016.

Such tensions have hit Turkish public opinion, with 83 percent holding unfavourable views of the US, a Center for American Progress poll showed this week.