AMMAN: Citing a “lack of support” and an “inability to function,” Jabhat Thuwar a-Raqqa has dissolved its Tribes’ Army, allegedly due to a “strangling Kurdish siege,” the latest in a series of squabbles and skirmishes that appear to have strained its alliance with the YPG in northern Syria, journalists and a Raqqa-based rebel commander told Syria Direct on Tuesday.

The reportedly 2,000-fighter strong Tel Abyad-based Tribes’ Army formed by Sunni Arab tribal leaders in Syria’s northern A-Raqqa province just over two months ago was, before Monday’s announcement, aligned with local brigade Liwa Thuwar a-Raqqa. Liwa, a former FSA affiliate in Raqqa province, had previously fought alongside Kurdish forces to wrest the Syrian border towns of Tel Abyad and Kobani from the Islamic State.

The Tribes’ Army and the brigade then merged to form a larger fighting force called Jabhat Thuwar a-Raqqa.

In November, Jabhat Thuwar a-Raqqa became the predominant Sunni Arab component of yet another larger alliance, the Syrian Democratic Forces, led by the Kurdish People’s Protection Units. The SDF, supported by the United States, was created to take on the Islamic State (IS) in north Syria.

Given past cooperation on the battlefield, the partnership between the Kurds and the tribes seemed to be a promising alliance, at first.

As part of Jabhat Thuwar a-Raqqa, the Tribes’ Army’s initial statements showed a willingness to work alongside YPG forces to achieve a shared objective to drive out IS fighters from northern Syria.

“The Kurds are our brothers, with the shared objective of liberating A-Raqqa province from the oppression of IS,” a Tribes’ Army commander proclaimed in an October 2015 video announcing the army’s formation.

However, cooperation between the Tribes’ Army and Kurdish forces in pursuit of that “shared objective” seems to have fallen apart three weeks ago, when the former issued a strongly worded announcement accusing the YPG of a litany of crimes against Arabs in north Syria.

The allegations included the machine-gunning of a Jabhat Thuwar a-Raqqa fighter in the Tel Abyad village of al-Anter, and the “systematic” forced displacement of Arab village and townsfolk.

In the same December statement, the Tribes’ Army warned the YPG to stay out of Arab lands, while calling for a United Nations investigation into reported YPG war crimes.

In response, Kurdish forces reportedly began a now three-week blockade of the Tribes’ Army in the Tal Abyad countryside after the army issued a written statement denouncing the YPG, reported al-Araby al-Jadeed on Wednesday, citing sources once close to the now-dissolved Tribes’ Army.

What remains unclear is why the Tribes’ Army disbanded rather than simply drop out of its alliance with the YPG.

Jabhat Thuwar a-Raqqa’s announcement did not blame any specific party for the dissolution of the Tribes’ Army. A senior Raqqa-based rebel commander who requested anonymity told Syria Direct Tuesday that it was the blockade against Liwa Thuwar and Tribes’ Army rebels in Tel Abyad that made the disbanding an “inevitability.”

“The YPG and its allies are imposing a strangling siege on Jabhat Thuwar a-Raqqa and the Tribes’ Army for the 15th consecutive day–they’re preventing them from entering Tel Abyad with their wounded, and depriving [those inside] of foodstuffs and all essential supplies,” reported the Raqqa is Being Slaughtered Silently media campaign on December 29, indicating a prolonged Kurdish effort to choke once-allied Arab rebels in Tel Abyad.

Kurdish YPG forces have reportedly used the weapons of blockade and encirclement to punish or sideline ostensibly allied Arab fighting brigades before, the same rebel commander told Syria Direct, even at the expense of the larger objective of battling IS.

“The YPG even stopped ammunition supplies to its ally Liwa Thuwar a-Raqqa during the fight for Kobani last June when it was battling the Islamic State,” said the Raqqa-based commander Tuesday.

It was not immediately clear what role the alleged blockade actually played in Jabhat Thuwar a-Raqqa’s dissolution of its two-month-old tribal partner. By removing a group whose recent statements threatened to unsettle an already-fraught alliance with Kurdish SDF forces, however, the Arab faction may have sought to sidestep outright conflict with its Kurdish partners. Jabhat Thuwar as of publication remains in the SDF alliance.

Although multiple sources confirm the Kurdish blockade of Arab rebels in Tel Abyad, at least one Kurdish journalist denies the allegations.

“There’s been no blockade; the Tribes’ Army was spread over a too-wide an area [to effectively blockade], and in addition to that, in areas where there are no Kurdish forces at all,” Mustafa al-Abdi, a Kurdish journalist reporting out of Kobani, told Syria Direct on Tuesday.

“A lack of support, and an inability to carry out its charged function … has made the Tribes’ Army a burden on Jabhat Thuwar a-Raqqa, compromising its essential mission to liberate A-Raqqa from the IS gangs,” reads Monday’s announcement. Source: Jabhat Thuwar a-Raqqa. Available on Facebook. 2015.

The internecine roots of a frayed alliance

The YPG’s reported blockade of its nominal allies in Tel Abyad is the latest escalation in a months-long string of tit-for-tat accusations and provocations between Arabs and Kurds in north Syria as a shared fight against IS collides with aspirations for territorial control.

Syria Direct has reported on tensions between Kurdish YPG forces and their allies, Sunni Arab rebel brigades in north and northeast Syria, over what they call the YPG’s encroachment of Arab territory. In March, Syria Direct reported on YPG units burning Arab homes in the far northeast Al-Hasakah province.

In a February report, Amnesty International denounced the “deliberate displacement of thousands of civilians and the razing of entire villages in areas under the Autonomous Administration … led by the Syrian Kurdish political party PYD.”

The YPG is the armed wing of the PYD.

Akram Salih, a correspondent embedded with YPG forces in Al-Hasakah told Syria Direct this past May in response to reports that the YPG was expelling Arabs from their lands in Al-Hasakah, east of A-Raqqa: "It's merely talk."

The YPG has denied driving Arabs from Kurdish territory. YPG commander Sipan Hemo told Kurdish journalist Mutlu Civiroglu in an interview this past October: Ethnic cleansing is "not what is happening on the ground."