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TOPSHOT – Smoke billows from a hilltop during clashes between fighters from Yemen’s southern separatist movement and forces loyal to the Saudi-backed president in the country’s second city of Aden on January 28, 2018. Yemen’s government accused southern separatists of an attempted coup on after they took over its headquarters amid fierce clashes in Aden. President Abedrabbo Mansour Hadi called for his troops to cease fire after fighting between his military and forces backing the separatists killed 15 people. / AFP PHOTO / SALEH AL-OBEIDI (Photo credit should read SALEH AL-OBEIDI/AFP/Getty Images)

From NPR:

This weekend’s bloodshed broke out Sunday in the southern port city of Aden, where forces loyal to the separatist Southern Transitional Council traded gunfire with loyalists of President Abed Rabbo Mansour Hadi. The scattered fighting has claimed at least 12 lives and injured scores more.

The two sides had shared an uneasy alliance since 2014, when they were united in their opposition to the Houthi rebels who seized cities in the country’s northwest, including the capital, Sanaa. Together, the STC and Hadi’s forces managed to repel the Houthis from Yemen’s southern governates and Aden, the large city where Hadi’s government had presided since its ouster from the capital.

As Reuters notes, the fighting follows the expiration of a deadline set last week by the southern separatists. Irate at what they call corruption and the deep erosion of public services in the areas still governed by Hadi, the STC had delivered him an ultimatum: shake up the cabinet and sack bin Daghir or face ouster. That deadline came and went without sign that Hadi had any intention of complying.

The Prime Minister of the Hadi government has labeled Sunday’s events a “coup”, but an official with the Southern Transitional Council claims that fighters only started using weapons because they were forced.

South Yemen, with Aden as its capital city, was once an independent state until 1990.

To make the matter even more complex, while Saudi Arabia supports the Hadi government, coalition member the United Arab Emirates has been focusing more on southern Yemen than the north. Al Jazeera notes that the UAE has more military and economic interests in the strategic location of Aden and the Bab al-Mandab Strait, which has led the UAE to support the sepratists.

“The Saudis believe any talk of secession will delegitimise the war effort, which they have repeatedly claimed is about restoring the government of President Hadi. Meanwhile, the Emiratis don’t want to see any party close to Hadi and Islah anywhere near power,” Maysa Shuja al-Deen, a non-resident fellow at the Sanaa Center for Strategic Studies, tells Al-Jazeera.

“The coalition is divided and no longer knows what they want.”