BEIRUT: Manbij risks becoming the next major flashpoint in Syria's tangled war, with Turkey threatening to expand its fight against Kurdish militia to the northern town, where US troops are based.
Amid escalating fears of a possible confrontation between Turkish and US forces in Manbij, just 30 kilometres (19 miles) south of the Turkish border, here is a short history of the strategic town.
Rebels, jihadists, Kurds
When Syria's conflict broke out in 2011, Manbij had a population of 120,000, including both ethnic Arabs and Kurds.
Rebels overran the town in 2012 and it fell to the Islamic State jihadist group two years later.
Its strategic location between the Turkish border and IS's de facto capital Raqa made it an important way station for the transportation of IS fighters, weapons, and money.
In 2016, the Syrian Democratic Forces (SDF) alliance waged a two-month battle for Manbij, backed by the US-led coalition's air strikes and advisors.
After ousting IS from Manbij in August 2016, the SDF handed over the Arab-majority town to an affiliated civil council.
It became a place of refuge for thousands displaced by the ongoing fighting against IS elsewhere.
US in Manbij 'buffer'
The US-led coalition has steadily backed the SDF since the alliance's formation since 2015, providing it with air strikes, advisors, and eventually weapons to fight IS.
After helping the SDF capture Manbij from IS, US military troops remained in the town, which lies in Syria's northern province of Aleppo.
Simultaneously, IS jihadists were losing territory all around Manbij to competing forces, with Russian-backed Syrian government troops to the south and Turkey-backed rebels to the north.
That put US forces stationed in Manbij at the centre of a de facto buffer zone between the bitterly divided factions.
In March 2017, the Pentagon said it had sent additional troops to the town "to deter parties from attacking any other parties other than ISIS itself."
But the US's presence there has drawn Turkish ire, with President Recep Tayyip Erdogan saying the troops should just withdraw.
"They (Americans) told us they will pull out of Manbij. They said they will not stay in Manbij... Why don't you just go?" Erdogan said in February.
Turkey eyes Manbij
The SDF is dominated by the Kurdish People's Protection Units (YPG) -- a group Turkey sees as the extension of an outlawed Kurdish faction in its own southeast.
Ankara fears a powerful Kurdish presence on its southern border and was enraged when the SDF took Manbij, saying it had been promised the US-backed militia would not expand west of the Euphrates River.
Senior Turkish officials have been threatening to capture Manbij ever since.
Just weeks after the town was taken, Ankara launched a cross-border operation just north of Manbij, fighting both IS and the SDF for eight months.
On January 20, Turkey and its Syrian rebel allies opened a fresh front in the northwestern Kurdish-controlled enclave of Afrin.
They captured Afrin city on March 18, and Erdogan immediately repeated his pledge to move on Manbij next.
NATO allies clash?
Last month, the US and Turkey vowed to work together to solve the Manbij dispute, with Turkey's foreign Minister saying a deal had been agreed that would see Kurdish fighters withdraw from the town.
But with US President Donald Trump's surprise firing of Secretary of State Rex Tillerson, it is unclear whether such an agreement is still in place or will be implemented.
A Turkish assault on the town could risk sparking an unprecedented conflict between two otherwise allied powers.
"Manbij, this little Syrian city just 30 kilometres south of the border, is now the flashpoint between two NATO allies over a substate actor, the YPG," said Aaron Stein, a fellow at the US-based Atlantic Council.
He said Erdogan's threats towards Manbij should not be taken lightly.
"They will figure out a way to go there, perhaps by forcing the US to make concessions through the prospect of intra-NATO war," Stein told AFP.