(AFP) - ISIS will fight ferociously for its Syrian bastion Raqa, but the battle will also be complicated by complex relations between Washington and its allies on the ground.
The divisions and distrust between different sectors of the anti-ISIS coalition may cause more problems for the coalition than ISIS.
Both US officials and the Kurdish-Arab Syrian Democratic Forces alliance leading the battle have already said it will be lengthy.
"As in Mosul, the fight will not be easy and there is hard work ahead," US Defence Secretary Ashton Carter said in a statement after the assault began. SDF spokesman Talal Sello echoed that warning, saying the operation, dubbed "Wrath of the Euphrates", "will not be easy".
"ISIS will defend its bastion knowing that the loss of Raqa will mean it is finished in Syria."
Two years after it declared its self-styled "caliphate", ISIS is facing a moment of truth, under unprecedented pressure as US-backed forces try to oust it from its two largest population centers: Raqa and Mosul in neighboring Iraq.
The group has already lost large swathes of territory in both countries, but the two battles now under way are set to be the hardest yet.
Romain Caillet, a specialist on jihadist movements, said Raqa was home to a "large group of foreign fighters with their backs against the wall".
With the main routes to Turkey severed, ISIS fighters have no way to evacuate their families, and nowhere else to go, he said.
"Because of that, they will probably fight until the end."
Coordinating two battles
Since the Syria operation began late Saturday, SDF forces said they had advanced around a dozen kilometers from the town of Ain Issa, previously their closest position to Raqa, some 50 kilometers south.
But the jihadists were already fighting back with a favorite tactic: suicide car bombs, dispatching five in a single day in the north of Raqa province.
The US-led coalition has some 50 advisers on the ground helping the SDF, but may find itself spread increasingly thin and struggling to coordinate as it wages two major battles across the Syria-Iraq border.
American officials have acknowledged the challenges involved in coordinating and synchronizing the disparate forces involved in the two offensives, as well as deciding how to deploy its air power.
The fight for Raqa is also complicated by a major challenge: politics. The SDF has become the US-led coalition's key partner in the campaign against ISIS in Syria, but neighboring Turkey considers the SDF's main component a "terrorist" group.
Ankara says the Kurdish People's Protection Units (YPG) that dominates the SDF is an affiliate of the outlawed Kurdistan Workers' Party (PKK), which has waged an insurgency inside Turkey.
In August, Turkey launched its own operation inside Syria, targeting both ISIS but also the YPG, in a bid to prevent Kurdish forces from expanding the semi-autonomous territory already under their control.
Mutual suspicion among allies
In launching the assault, the SDF said it had a deal with Washington ensuring that Turkey would not be involved in the battle.
But US officials say they are in "close contact" with Ankara about the operation, while also acknowledging the delicacy of the situation.
"We want this to be as coordinated as possible, recognizing that there will be a mix of forces on the field and that many of those forces of course do not see eye to eye," said Brett McGurk, the US president's envoy to the anti-ISIS coalition.
For the Kurds, leading the Raqa operation is a chance to cement their territory and bolster their reputation, said Mutlu Civiroglu, a Kurdish affairs analyst.
"The Kurds agreed to lead the operation to protect the territory under their control," he told AFP, adding that they "want to show to the world that they are the main power in defeating ISIS".
"They are hoping that in return... the US will politically recognize their
political, administrative system on the ground."
Syria's main opposition group also regards the Kurds with suspicion, accusing them of displacing Arab civilians as they capture territory and pursuing a "separatist" agenda.
"It should be the rebels, backed by Turkey and the US-led coalition, that liberate Raqa," said Ahmed Ramadan, a spokesman for the opposition National Coalition.
Follow Middle East and Terrorism on Twitter
Copyright - Original materials copyright (c) by the authors.