JARABLUS, Syria (Reuters) - Rebel commander Adnan Abu Faisal and his army are encamped near the frontline in northern Syria, waiting to launch an offensive on his home city of Manbij.

FILE PHOTO: Turkish military vehicles ride at the Bab el-Salam border crossing between the Syrian town of Azaz and the Turkish town of Kilis, in Syria January 1, 2019. REUTERS/Khalil Ashawi

But they are not the ones who will decide whether to march on the strategically important city, held for more than two years by Kurdish forces supported by the United States.

The decision will depend on Turkey, the main backer of Abu Faisal’s group, and on how contacts evolve between Washington and Ankara over the United States’ plans to withdraw forces from Syria, a move set to reshape a major theater of the war.

(graphic: tmsnrt.rs/2RgCxxb)

The United States and Turkey are allies both in the NATO defense alliance and in the fight against Islamic State, but Ankara sees the Kurdish YPG forces that helped the U.S.-led coalition drive IS out of Manbij in 2016 as a security threat.

The YPG fear the U.S. withdrawal will open the way for a threatened Turkish attack into northern Syria, including Manbij, but U.S. President Donald Trump has warned Turkey of “economic devastation” if it goes ahead with the attack.

Abu Faisal’s fighters are awaiting orders near Jarablus, a town held by Turkey and its Syrian rebel allies about 35 km (22 miles) south of Manbij. The frontline in the area runs through open farmland where wheat and corn are usually grown.

“We are ready with our forces ... for ‘zero hour’ to begin any military action,” Abu Faisal, whose forces have more than 300 vehicles including pickup trucks and armored vehicles provided by Turkey, told Reuters.

“Preparations are going at full speed,” he said.

Abu Faisal, 36, was an army captain before Syria’s civil war began in 2011 but defected from the Syrian army in 2012 to join the fight against President Bashar al-Assad.

Abu Faisal helped wrest control of Manbij from the Syrian army early in the conflict but fled when it was seized by Islamic State in 2014 and has not set foot there since then.

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The YPG have also left Manbij but retain influence over the Kurdish-allied groups that hold the city 30 km (20 miles) from the border with Turkey.

Manbij lies near the junction of three separate blocks of territory that form spheres of Russian, Turkish and, for now, U.S. influence.

The U.S. military pullout will not only leave Kurds exposed to possible confrontation with Turkey but will also open the way for the expansion of Russian and Iranian sway into the areas that U.S. forces will be leaving.

The U.S. military deployed into Syria as part of the fight against Islamic State but officials later indicated wider objectives included containing Iran, Assad’s main regional ally.

Late last month, the YPG called on Assad’s forces to protect Manbij from attack by Turkey. Syrian government forces, which are backed by Russia, answered the YPG appeal by deploying outside Manbij.

Abu Faisal’s rebel fighters, backed by Turkish forces, made their own advance towards the city the same day but stopped short of an attack. Since then, Turkey has been engaged in diplomatic contacts with Washington and Assad’s Russian allies.

The Kurds who control swaths of northern Syria have turned to Russia and the Syrian government since Trump’s announcement, hoping to secure a deal that keeps Turkey at bay and preserves their autonomy within a reformed Syrian state.

Abu Faisal said “political understandings” would determine whether an attack went ahead, reflecting the influence of foreign powers in the Syrian conflict. A political solution that spared blood would be welcome, he added.

TRUST IN TURKEY

For Abu Faisal, the YPG -- People’s Protection Units -- is no less of an enemy than IS or Assad.

Turkey views the YPG as an extension of the Kurdistan Workers’ Party (PKK), which has waged a 34-year insurgency in Turkey for Kurdish political and cultural rights, mostly in southeastern areas near Syria.

A top Kurdish politician told Reuters this month the Kurds had presented Moscow with a road map for a deal with Damascus.. Syria’s deputy foreign minister has said he is optimistic about renewed dialogue with the Kurds.

A deal between Damascus and the Kurds would piece back together the two largest chunks of Syria and leave one corner of the northwest under the control of anti-Assad insurgents who have been driven out of many of the areas they once held.

Abu Faisal -- head of the opposition’s Manbij Military Council in exile -- says it would be a catastrophe if Assad were allowed to recover Manbij. He warned this would trigger yet more displacement of civilians fleeing a return of Assad’s rule.

His priority is to secure the return home of Manbij residents who have been living either as refugees in Turkey or in nearby areas of northern Syria that are controlled by Turkey and its Syrian allies.

“There cannot be acceptance of any political solution or military solution except with the return of these displaced people to their city,” Abu Faisal said.

“Our goal is to reassure the people of Manbij that its people will run the affairs of this city,” he said.