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Input: 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 new fault that has opened between  Hadi  and  his  erstwhile allies in the STC adds another dimension to a war already packed with a dizzying array of players â and a long  tortuous history dating back at least to 1990. That's when South Yemen  a formerly independent state with Aden for its capital  agreed to unification with its northern counterpart. The union has never quite been an easy one  strained by a 1994 civil war and more recently  calls for greater autonomy in the south.
Add to that latent friction the bloodshed of recent years  which has seen Yemen's internal conflicts take on the character of a proxy war among competing powers in the Gulf region. The Houthis  a Shiite group based in the northwest  have been backed by Iran  while Saudi Arabia has led a coalition conducting an air campaign since 2015 supporting  Hadi  and  his  Sunni allies.

Bloodshed Roils Yemen's South Further Complicating An Already Complicated War : The Two