Warning: Graphic images below.

Everyone was silent as we watched the flare spiral slowly to the ground, burning brightly, high above the smoke, noise, and flame of the burning oil refinery on the flat horizon. The Kurdish fighters then seemed to waken suddenly, shouldering their weapons and firing bursts of hot red tracer into the Islamic State (IS) positions just ahead.

Six weeks earlier the jihadist group had launched a shock offensive on the city of Hasakah, northeast Syria, capturing almost half of it and initiating a bloody three-way struggle between IS, the Syrian regime and the Kurdish YPG forces, as well their allied militias. On this August night, however, the next few hours would see IS finally expelled from the city, and the YPG in almost total control of their first provincial capital in Syria.

Hasakah is the commercial and political center of the northeastern governorate of the same name, one of the most ethnically and culturally diverse in Syria. Thinly populated before French colonial rule in the early 20th century, the flat and dusty region is home to the majority of Syria's Kurdish population, as well as Assyrian and Syriac Christians, and Sunni Arab tribes, many of whom were planted in the region in the 1960s and 70s by the Syrian regime in an act of colonial settlement to dilute the region's Kurdish majority.

The result is one of the most tangled and confusing theatres of the Syrian war, where Kurds, Arabs, and Christians vie or ally with each other as realpolitik demands, and each faction is divided into its own ethnic submilitias.

The Background to the Battle of Hasakah

The Syrian revolution failed in Hasakah, a region where decades of clientalist politics and land disputes with the Kurds saw the largest and most powerful Arab tribes firmly wedded to the regime. While supporters of the predominantly Sunni Arab rebellion accuse the Kurds of treachery for not supporting their cause against the regime, the Kurds, represented by the PYD party and its YPG militia, aimed from the start to maintain a distance from what they viewed as an Arab civil war, in a bid to consolidate their newly-won autonomy.

Many of Hasakah's tribal militias that rose up against President Bashar al-Assad in 2011-12 had been armed by him in 2004 to put down a short-lived Kurdish rebellion against his rule, and their enthusiastic participation does not go forgotten by the Kurds. When regime forces, led by the local National Defense Force (NDF) militia, occasionally clashed with Kurdish forces, the YPG fought back, capturing vital infrastructure in the city center in the process.

Watch **Pushing Back the Islamic State: The Battle for Rojava (Dispatch 1):**

When the YPG and the rebels began to clash over the border town of Ras al-Ayn in summer 2013, a bloody conflict within the Syrian war was initiated that would see the Free Syrian Army (FSA) align with both IS, then known as ISIS, and the jihadist factions Jabhat al-Nusra and Ahrar al-Sham against the YPG. Ultimately, as IS grew in power, it would expel its erstwhile allies from the region, first extinguishing the FSA as a force in Hasakah, then turning on Ahrar al-Sham and Jabhat al-Nusra until they too were forced to submit or flee.

By June 2015, only YPG, IS, and regime forces survived in Hasakah, with the first two locked in a bloody back-and-forth existential war across the region while the Syrian army (SAA) garrisoned the central blocks of the two largest cities, Hasakah and Qamishli. The YPG, now backed by US airstrikes, had become the most powerful single actor in northern Syria while the regime was looking weaker than ever before, crumbling beneath rebel offensives in the northwest and IS assaults in the country's central desert belt.

The lightning-fast success of the YPG's offensive against Tal Abyad, IS's most important border crossing with Turkey, that started in May, tarnished the image of the ever-expanding caliphate that IS propaganda is at pains to disseminate. Now, with IS losing its vital supply lines to Turkey and the YPG a mere 30 miles from the gates of its capital city Raqqa, the group was in need of an easy victory; and no opponent in Syria was weaker than the regime.

IS Shock Troops Move In

The early June IS offensive saw regime troops crumble, losing control of much of southern and central Hasakah in a matter of days. Instead of regular SAA troops, Hasakah was seemingly garrisoned by Assad-loyalist NDF militias, entirely inexperienced in combat except for occasional clashes with the YPG — which they invariably lost — and no match for the elite troops IS placed at the spearhead of its offensive.

Tanks abandoned by IS in the city's south-central al-Neshwah district are stenciled with "Jaysh al-Khilafa 335," presumably a sub-unit of the Army of the Caliphate force. This is believed to be a Russian-speaking elite assault brigade which is better trained, equipped, and paid than ordinary IS infantry and shuffled across Syria and Iraq to head important offensives.

Insignia on the abandoned IS tank. Photo by Aris Roussinos

Even allowing for post-mortem bloating, the IS bodies scattered across Neshwah were those of large, powerful men, some dressed in the Russian Gorka 3 uniform affected by Chechen jihadists in Syria. As the regime troops fell back, abandoning bases and equipment behind them, the YPG quickly surrounded the IS advance guard in south-central Hasakah, cutting off their vital supply line to the south and preparing for the main assault. When it came, it would be deadly.

With the circle closed around IS, the effect of coalition airstrikes was devastating. B1-B bombers circled the city constantly, striking IS wherever they moved. On a tour of the devastated Neshwah district — until a few weeks ago a regime stronghold — an Arab YPG officer, Mahmud al-Felluh, a defector from the regime's intelligence services, took VICE News on a grim tour of demolished houses and rotting jihadists.

The Grim Aftermath of Airstrikes

Feral dogs hung about the stinking ruins, with human bones, picked clean, lying around the dusty streets. On a roof, a blackened torso and a pair of legs, still belted in combat trousers, slumped headless where the blast had thrown him. The officer held his nose against the stench as he pointed out the dead. Chechen, Saudi, Kazakh, Felluh told VICE News as he pointed out each fighter, attributing nationalities to them with little discernible evidence.

"The clashes were very heavy," he told VICE News. "IS entered with more than 4,500 fighters into Neshwah and Sharia neighborhoods. Of course the regime withdrew completely from this neighborhood. Then our units, YPG, Asayish, al-Sanaddid, and YPJ started to besiege the city, we established a security cordon around Hasakah and besieged IS inside the city, so nobody could flee. And the clashes started here, all those who entered here were killed. We also seized armored vehicles and tanks but now this area is completely cleaned."

Arab civilians were slowly filtering back to Neshwah, shaking the hands of YPG fighters and thanking them, and accusing the NDF of allowing IS to enter their district without fighting back. "Who sold Hasakah?" demanded one middle-aged Arab woman in a hijab. "How did they sneak in and enter so safely and quietly? They entered the city very quietly and freely," she added.

"Now I am here with the protection of the YPG, with the protection of God and the YPG. I am afraid of IS. After IS entered our area there was terror, terror, terror, killing, and destruction. Some cars were there and helped us, taking us to Qamishli. Half of us, half of Hasakah's population is now in Qamishli. They received us in Qamishli, in schools. We called on the YPG, I am one of those who called on the YPG. It was the YPG who took me there in their white pickup."

The ruins of a residential building in Neshwah district, destroyed by coalition strikes. Photo by Phil Caller

Arab Support for the Kurds?

Stung elsewhere in northeastern Syria by accusations of discriminatory policies against Arabs, the YPG will need to convince local populations that they will guard their interests. There is a claim commonly made by both analysts and IS supporters that Sunni Arabs in Syria will invariably support IS over the YPG, on ethnic grounds.

But in this middle-class Sunni Arab district that had always supported the regime — until the regime fled — and had shunned the moderate revolutionaries of the FSA, the PYD will likely have a reasonable chance of securing popular support for their rule, as long as they can provide security and basic services and what passes for a normal life in Syria. As for IS, while its constant output of increasingly baroque atrocity porn may thrill its horde of teenage internet fans, it is hardly designed to make ordinary Syrian civilians welcome them as liberators.

Having abandoned Neshwah, the regime has established a new checkpoint on a roundabout a few meters away, where NDF militiamen in shorts and flipflops eyed the YPG warily across the road. Black-turbanned Assyrian Christian militiamen of the MFS, a YPG ally, sat on plastic garden chairs facing them, the heavy machinegun barrel on their pickup truck pointing squarely at regime positions. Regime flags fluttered from the rooftop of the apartment blocks facing us, as smoke from a burning petrol dump clouded the horizon.

Watch **Night Operation Against the Islamic State: The Battle for Rojava (Dispatch 2):**

"This base belonged to the regime, the regime fled and left its base. The regime is fighting on its frontline and we are fighting on our frontline," Felluh told VICE News, before adding for emphasis, "The regime is over there, and we do not have any relations with the regime."

With IS surrounded in the city's southern al-Zuhor neighborhood, the YPG took us to a frontline position in the Red Villas district, an unfinished American-style housing development where two dead NDF soldiers lay unburied in the shell of a suburban house. It was dusk, and the YPG were preparing to provide suppressing fire from here onto IS positions in al-Zuhor, a few hundred meters away across a slight incline.

Through a strange coincidence of war, I had met the commander in Red Villas back in March, when he and his platoon were fighting for the Iraqi town of Sinjar, still mostly held by IS. They had been sent here to Hasakah as reinforcements as soon as IS attacked the city, and he retained a healthy respect for his opponents.

"IS fights professionally," he asserted, "Maybe not all of them but there are professionals among them. They are trained well, they are trained abroad. We can say from all over the world, IS gathers militants and trains them in the camps for six months or one year and recently we could see that the ones who were killed here had some documents from Mosul. They had trained in Mosul for six months then came here. They were defeated in other places. So they wanted to boost their morale with Hasakah, to boost the morale of their militants and members. It has been 40 days non-stop during the days and nights. There are heavy clashes and it comes at a heavy cost."

A dead NDF soldier allegedly killed while fighting IS. Photo by Phil Caller

Indeed, over the two previous days this platoon had lost five men just retaking the tiny mud brick hamlet adjoining Red Villas. The hollow-eyed fighters showing VICE News around pointed out the homemade armored vehicle, burned out by an IS rocket, where two of their number had been killed. They led me to the IS fighter who had killed their friends, lying on his back on a pile of rubble. A hole, filled with crawling maggots, had replaced his face. "Our comrade shot him in the head with a 23mm," my guide said matter-of-factly.

Clean-Up Operation

Radios crackled as the men moved into position, picking over IS bodies in the rubble to grab an icebox full of chilled water from a frontline outpost as they took up firing positions. The main YPG assault on al-Zuhor was coming from the west, where the Kurds were quietly infiltrating the empty streets before launching their attack. The gun truck reversed out from behind a wall as the gunner squinted down the barrel at the IS position they'd been ordered to suppress.

"We've had IS surrounded for about a week," said YPG commander Botan Ahmed. "One small area remains. They are surrounded there, and now we are to going to clean that area. Our comrades are attacking from the other side, and we are going to fire at that area to support our comrades, and make them [IS] lose their concentration."

When the command came, first the gun truck then the riflemen and machine gunners poured tracer fire into the target, wave after wave of airstrike obliterating the IS positions in balls of bright sparks. We counted the bombs for hours, strike after strike. There were, by a large margin, far more coalition airstrikes in one night here in Hasakah than in a month on the Mosul frontline, an indication, perhaps, of the Pentagon's priorities.

YPG commander Botan Ahmed. Photo by Phil Caller

Uneasy Truces and Understandings

At one point, the circling coalition jet flew away and Ahmed alerted us that the Syrian Arab Air Force was about to bomb IS, to prevent a desperate push into regime territory from al-Zuhor.

Sure enough, a helicopter slowly passed over, dropped two bombs, and flew away. As soon as the helicopter left, the coalition jet came back, and began to bomb again. While the coalition denies any military coordination with the regime, the YPG commanders on the ground knew who was about to bomb, and where, in advance, and the US jet, fortuitously or not, managed to avoid sharing airspace with Assad's air force.

The YPG themselves share space with the regime, in a tense détente that is neither alliance nor open opposition. Regime forces are allowed to use the fastest road between their garrison and airport in Qamishli and Hasakah, with the YPG taking a circuitous side route to avoid them. In Hasakah itself, the two forces share central roads for short distances, with the YPG allowed to use NDF-held stretches of road when necessary, and the NDF permitted to travel through YPG checkpoints to resupply the outposts on the fringes of their territory.

The détente is not absolute — the YPG frequently relay anecdotes of pushy SAA officers being ordered out of newly-captured territory at gunpoint, and rumors of minor clashes are constant — but for now, the system works. Traveling through regime-held territory with a YPG escort, we witnessed a volatile situation where NDF checkpoints stud one side of the road, and YPG outposts the other. On the YPG side, the Kurdish fighters, buoyed by victory and smart in their digital camouflage uniforms, look more like a professional army than the NDF militiamen padding around in vests and sandals or snoozing in their beach chairs.

YPG soldiers pose for photo opportunity, opposite a regime checkpoint. Photo by Phil Caller

Trolling the Regime

The greatest risk of conflict between the two remaining sides in Hasakah is over the YPG's appropriation of territory, including SAA bases, captured from IS. Over a period of days, YPG forces removed abandoned tanks, armored vehicles, and trucks on flatbed lorries from these bases, raising the YPG and YPJ flags over their entrance gates as frayed posters of Assad surveyed the scene with aloof detachment.

The Syrian regime, according to the YPG, demands the return of these bases and the districts of the city surrounding them, and for now the YPG has no inclination to return them to the poorly-disciplined troops who abandoned them to IS. "Normally one protects one's positions," mused a young YPJ commander as she watched the stripping of the base across the road, "but bit by bit, the regime leaves its positions. The regime knows there is no place for it in Hasakah."

As NDF militiamen glared at them, YPG special forces troops performed a victory dance to bawdy electro-folk outside one base, handing out slices of chilled watermelon and bunches of grapes in an impromptu street party, part an expression of relief and thankfulness, and part trolling. Not far away, the blackened bodies of the last IS defenders of al-Zuhor rotted in the sun. These weren't the powerful shock troops found in the city center, but slender teenage boys, scattered about where the bomb blasts flung them.

It seems likely that when defeat seemed inevitable, IS left behind expendable cannon fodder to delay the YPG advance while withdrawing their best troops to fight another day. But neither their elite troops nor their teenage levies had any effective military response to the combined power of US jets in the air and the YPG on the ground. A wave of suicide truck bombs released from the hamlets under their control has delayed the Kurdish advance, rather than halted it. A force with a doctrinal reliance on offensive action, IS now have to conduct a fighting withdrawal to their next desert strongholds, far to the south and east.

What's Next?

As IS was pushed out of the city, the battle moved to the Arab villages on the city's southern fringe, where YPG and YPJ infantry, supported by airstrikes, penetrated further south towards the south Hasakah desert and IS heartlands. The likely next target will be the strategic desert town of al-Hawl, straddling the M4 highway between IS's Syrian possessions and the long-stagnant Sinjar battlefront.

Beyond al-Hawl lies the city of Shaddadi, the IS military capital for Hasakah, a region of rich oil fields, and a stronghold of pro-IS sentiment among the local Arab tribes. Unless the YPG can draw deeper support from the region's Arab population, and perhaps inspire significant defections from regime forces, the Kurdish-led forces will find these desert Arab areas harder to rule than conquer, with any displacement of the local population providing fertile ground for accusations of ethnic cleansing.

Within the next few weeks and months, the YPG will likely reach the limit of their natural zone of expansion in northeast Syria. Until then, their proven ability as the coalition's only effective boots on the ground here will see their conquests backed by western air power as long as they remain useful to the Pentagon. What happens after that is yet to be seen, and will be decided in Washington and Ankara as much as on the ground in Syria.

Follow Aris Roussinos on Twitter: @arisroussinos