All you need to know about the UAE-backed separatists who have claimed control of Aden and other provinces.

Yemen’s southern separatists have broken a peace deal with the country’s internationally-recognised government and claimed sole control of the regional capital of Aden, threatening to resume fighting between the two ostensible allies.

In a statement on Sunday, the Southern Transitional Council (STC), which is backed by the United Arab Emirates, declared a state of emergency and said it would “self-govern” the key southern port city and other southern provinces.

The separatists accused Yemen’s government, which is supported by Saudi Arabia, of corruption and mismanagement.

Alkhader Sulaiman, a spokesman for the STC based in the United States, told Al Jazeera the separatist group was forced to take matters into its hands because of the government’s failure to provide basic services.

“This is not an event that just sprung out of nowhere. This is a pile-up of mismanagement, misgovernance, especially in south Yemen, which has been Houthi-less for four years now. Unfortunately, things have deteriorated humanitarian wise. The situation, in terms of basic services, is minimal,” he said.

The move threatens to renew the conflict between the nominal allies in Yemen’s multifaceted war as the foreign minister of the internationally-recognised government said the STC decision is a violation of a power-sharing agreement signed last November in the Saudi capital, Riyadh.

“The announcement by the so-called [Southern] Transitional Council of its intention to establish a southern administration is a resumption of its armed insurgency … and an announcement of its rejection and complete withdrawal from the Riyadh agreement,” Foreign Minister Mohammed al-Hadhrami said in a statement.

The deal was signed after the STC seized Aden in August 2019 in fighting, which was dubbed a “civil war within a civil war”.

Abdullah Baabood, a visiting professor at the National University of Singapore’s Middle East Institute, said the collapse of the Riyadh Agreement was inevitable.

“It really is a death knell to the Riyadh agreement, which was actually born dead anyway from day one, as each party walked away with a different interpretation and they had different objectives out of it. It was clear that it wasn’t going to work,” he told Al Jazeera.

The separatists and forces loyal to exiled President Abd-Rabbu Mansour Hadi have fought together in the Saudi-led coalition’s war against Yemen’s Houthi rebels, who control the capital Sanaa and mostly northern parts of the war-torn country.

When the Saudi-led Arab coalition intervened in March 2015 to fight Houthi rebels who had taken control of key cities in the country including Aden, the southern separatists had joined hands with forces loyal to Hadi.

Aden was regained by Hadi’s forces in July 2015, and began to function as the interim capital with the northern city of Sanaa firmly under Houthi control.

Yet tensions in Aden rose in April 2017 when Hadi accused the city’s governor, Aidarous al-Zubaidi, of disloyalty and dismissed him.

On May 11 that year, following mass protests against al-Zubaidi’s removal, the STC was formed, with the former Aden governor chosen to preside over the 26-seat council.

The body immediately declared its intention to “reinstate the Southern State” – a reference to the former South Yemen republic, which existed from 1967 until 1990.

Hadi immediately denounced the STC as illegitimate.

Roots and UAE backing

Since 2016, the UAE has provided military and financial backing to the Security Belt, a now STC-dominated paramilitary group comprised of some 90,000 Yemeni fighters.

In 2015, the southern coalition relied on the Security Belt to secure territories in the south and reinstate the government in Aden, with Hadi’s forces regaining full control of the city in July.

While secessionist sentiment in the south has been fuelled by recent political developments, it is rooted in its past.

The British established a colony in Aden in 1839 and remained there until withdrawing in 1967, when Aden joined other southern regions to form an independent South Yemen republic.

In 1970, a socialist republic was declared, which forged close ties with the erstwhile Soviet Union.

Outside of Aden, smaller separatist movements in other southern provinces do not back the STC’s vision of re-establishing the South Yemen republic through the use of force, with the UAE-backed group unlikely to easily win the allegiances of fragmented groups in the south.