Yemen war: Who is the Southern Transitional Council?
Tensions continue to escalate in southern Yemen after the UAE-backed Security Belt Forces (SBF) lost territory on Thursday to troops loyal to the Saudi-backed government of President Abd Rabbuh Mansour Hadi.
Yemen's foreign minister has accused the UAE of carrying out air strikes on government positions in Aden, which killed over 30 soldiers.
Despite fighting in the same coalition against the Iran-aligned Houthi rebels, the UAE fell out with Hadi's government after Abu Dhabi accused Hadi of aligning with the Islah party, who it views as ideologically close to the Muslim Brotherhood.
But the roots of this latest flashpoint have their origins in Yemen's modern political history stretching back long before the country's current civil war.
Who is the STC?
Formed in 2017, the Southern Transitional Council is a secessionist movement focused on gaining independence for South Yemen. Comprising of 26 members, the STC includes five governors from Southern Yemen and two former government ministers.
The STC emerged after Hadi fired Aden governor Aidarus al-Zoubaidi for alleged disloyalty in April 2017.
Hadi accused Zoubaidi of prioritising the Southern Yemen independence movement over a united Yemen. Following Zoubaidi's sacking, mass rallies were held in Aden to protest Hadi's move.
The STC was subsequently created a month later, with Hadi describing the council as illegitimate.
Why does the STC want independence?
The call for independence has been a source of contention for over a century. South Yemen's origins can be traced back to 1874 when the British Empire created the Aden colony and Aden protectorate.
Following its independence from Britain, South Yemen was formed in 1967 and later became the People's Democratic Republic of Yemen in 1970, a Soviet Union-backed Marxist-Leninist state, the only one of its kind in the Middle East during the Cold War.
The Soviet Union's collapse led South Yemen to merge with the North to form a unified Yemen. That union, however, lasted only four years and led to the 1994 civil war, when South Yemen army units accused northern president Ali Abdullah Saleh's forces of corruption.
In 2007, the Southern Movement, also known as the al-Hirak al-Janoubi, was formed. Its stated aims were to demand equality under the law and a change in relations between north and south in the context of a united Yemen.
The Hirak was met with repression by Saleh's government. This set the foreground for the Southern independence movement to flourish during the Arab Spring after the Hirak began to champion Southern independence in 2009.
Who backs the STC?
In 2016, the UAE helped create the SBF in southern Yemen. The SBF included many militants who supported a secessionist movement in Southern Yemen.
Forces within the SBF supported the STC, with the aim of establishing an independent South Yemen state. Since its formation, the SBF has played a crucial role in the Saudi-led coalition before the recent escalation.
Its successes came in part due to being militarily backed by the UAE. The backing included training of SBF fighters in Abu Dhabi and the supply of military equipment.
After receiving training, the SBF was dispatched to fight Houthi forces operating inside southern Yemen.
Emirati backing was crucial in helping the STC gain Aden, which has been under its control since 2018.