Syria's SDF: US-backed alliance who captured IS-held Raqa

Beirut: The US-backed Syrian Democratic Forces alliance of Kurdish and Arab fighters who captured Raqa city from the Islamic State group on Tuesday was formed in October 2015.

The SDF has since emerged as a key force fighting IS in northern Syria, and is the main ground force partnered with the US-led coalition against the jihadist group.

The SDF is made up of Kurds, Arab Muslims and Christians who have joined forces to battle IS.

The alliance includes an estimated 30,000 fighters -- some 25,000 Kurds and 5,000 Arabs.

Its backbone is the Syrian Kurdish People`s Protection Units (YPG), which had already dealt IS several defeats including the capture of the key border town of Tal Abyad.

Along with the all-female Kurdish Women`s Protection Units, the SDF includes Arab factions, Syriac Christian fighters and Turkmen units.

After the US-led coalition launched its first air strikes against IS in Syria in September 2014, Washington struggled to find a reliable partner on the ground.

A much-touted $500-million programme to build a rebel army to fight IS collapsed after many candidates failed the screening process and one group surrendered equipment to an Al-Qaeda affiliate.
After the SDF was formed, the White House announced the first sustained deployment of US special forces to Syria, reversing a longstanding refusal to put boots on the ground.

Around 50 special operations personnel were deployed in northern Syria, and the number has now grown to around 500 US troops.

Senior US commanders and Washington`s envoy to the coalition Brett McGurk have met top SDF chiefs during visits to northern Syria.

Washington said in June it would supply weapons directly to the YPG despite objections from ally Turkey, which sees Kurdish ambitions in Syria as a threat to its own security.

In November 2016, the SDF announced its operation "Wrath of the Euphrates" aimed at ousting IS from Raqa province, including the group`s de facto Syrian capital Raqa.

In the months that followed, the alliance gradually closed in on the city, first sweeping into territory to the north before closing in from the east and west.

One key challenge was the battle for the town of Tabqa and the neighbouring dam, around 40 kilometres (25 miles) west of Raqa.

That operation began in late March, when US forces airlifted SDF troops behind IS lines.

Subsequent heavy fighting raised fears for Tabqa`s vast dam, which the SDF eventually seized along with the town on May 10, severing a key IS route out of Raqa.

In early June, SDF forces entered Raqa for the first time, penetrating its Old City a month later after air strikes by the US-led coalition smashed two holes in the ramparts. 

On September 1, the group announced it had ousted IS from the historic district, bringing it closer than ever to the jihadists` best-defended positions.

By late September, SDF forces had taken control of 90 percent of the city, cornering IS fighters in Raqa`s stadium, a few surrounding buildings and a major hospital.

On October 17, SDF spokesman Talal Sello told AFP the US-backed fighters finally had "taken full control of Raqa" from IS.

Ankara considers the YPG a "terrorist" group, an offshoot of the Kurdistan Workers` Party (PKK) that has waged an insurgency inside Turkey since 1984.

Turkey launched an operation inside Syria on August 2016 alongside allied opposition forces and managed to retake the IS stronghold of Jarabulus and the symbolically important town of Dabiq.

The operation also sought to check advances by Syrian Kurds, and Turkish forces have carried out air strikes against YPG positions.

But Ankara failed to convince Washington to hold off on the Raqa operation and find an alternative partner on the ground.

It reacted with fury to Washington`s decision to arm the YPG, despite US assurances that the weapons supplies would be limited and monitored.