A US-backed umbrella group mainly consisting of local Kurdish forces launched a new offensive on DAESH on Tuesday as they advance towards the city of Raqqa.
The Syrian Democratic Forces (SDF), an alliance of various militias formed last year to battle against DAESH, has been gaining ground against the group with the support of US-led air strikes.
To date, the majority of territorial gains have been in predominantly Kurdish regions of northern Syria where the YPG, which comprises the main bulk of the SDF fighters, enjoy a degree of acceptance from locals.
However, the offensive of Raqqa, a predominantly Arab city where DAESH has set up their de facto capital, marks a new phase in the war against the group.
Although there are some Arab brigades in the SDF alliance, their numbers are not enough to take on the responsibility of leading the offensive.
According to the UK-based Syrian Observatory for Human Rights, which monitors the war in Syria, an unspecified number of SDF fighters set off southwards from the town of Tel Abyad near the Turkish border towards the town of Ain Issa.
The SDF aims to first take control of the countryside in the north of the Raqqa province before moving on to the city itself, spokesman Talal Silo told Reuters.
The launch of the offensive comes just days after US Army General Joseph Votel, who was recently appointed as Washington’s top commander in the Middle East, paid a secret visit to Syria on Saturday.
Votel arrived in northern Syria after entering the country from neighbouring Iraq to check on the progress of US forces advising the SDF in the battle against DAESH.
At the end of his visit, Votel told reporters that his confidence in the US's new strategy had "increased," adding that it is "working and working well."
However, there is concern among US allies in the Middle East over Washington’s strategy in Syria, as a fragmented opposition has made it difficult to find forces willing to fight against both DAESH and Bashar al Assad’s regime.
Turkey has been one of the most outspoken critics of US policy in Syria, particularly of its support for the SDF, because of the YPG’s association to the PYD.
The PYD has often been linked by Turkey to the PKK, a militant group that Ankara defines as a terrorist organisation and regularly carries out attacks on Turkish security forces and civilians primarily in the country’s south-east.
Washington has shied away from endorsing Ankara’s calls for the establishment of a buffer zone along Turkey's border in northern Aleppo, control of which would be handed to the Free Syrian Army once DAESH is cleared from the area.
Instead, Washington has chosen to support the SDF with approximately 200 military advisers on the ground, with another 250 set to join them soon.
The SDF was formed after the US abandoned its short-lived train-and-equip programme, which would have seen "moderate" Syrian opposition fighters given the means to take on DAESH before being deployed in Syria.
However, the US was unable to identify a sufficient number of fighters suitable for the programme, and the few who were sent into Syria were kidnapped and stripped of their weapons immediately after crossing the border.
While benefitting from US airdrops of weapons and ammunition, the SDF has also taken advantage of Russian air strikes on Syrian opposition forces to advance in northern Aleppo, where the YPG hopes to establish a corridor across the ethnically mixed region to link the territory it controls around the city of Kobane to its self-declared "canton" of Afrin.