Dubai (AFP) - An alliance between Huthi rebels and Yemen strongman Ali Abdullah Saleh, which jointly controls the capital Sanaa, has begun to unravel, threatening to further splinter a country already ravaged by war.
Witnesses say armed supporters of Saleh and the Huthis have spread across the city on the eve of a mass rally to mark the 35th anniversary of ex-president Saleh's General People's Congress, sparking fears of an intensification of violence in a country already ravaged by war, cholera and famine.
For three years, the Saleh-Huthi alliance has fought the Saudi-backed government for control of Yemen in a war that has decimated the lives of millions and brought the country to the brink of starvation.
Tension between Saleh and the Huthis is at an unprecedented high, threatening an unlikely alliance that has long been viewed as tactical at best.
The two sides have flung mutual accusations of treason over the past week, culminating on Wednesday in an open threat by the Iran-backed rebels who said Saleh would have to "bear the consequences" after he dismissed his allies as "militias" in a weekend speech.
- Enemy of my enemy -
Saleh's history with the rebels is long and complicated.
The Yemeni strongman, now 75, has waged six wars against the Huthis since the late 1970s, when he was president of then-independent north Yemen and allied with Saudi Arabia, which leads the Arab coalition now backing President Abedrabbo Mansour Hadi.
Saleh was elected Yemen's first president when the country unified in 1990 and remained in power until 2012, resigning after a year of protests-turned-clashes in a deal brokered by the Gulf Cooperation Council that guaranteed him and his family immunity.
He was succeeded by Hadi, then vice president, who emerged as his biggest political rival.
Saleh pulled an about-face in 2014 and realigned himself at the side of Abdul Malik al-Huthi, the Zaidi Shiite leader of the rebel Ansar Allah movement with ties to Riyadh's archrival Iran.
The Huthis drove the Hadi government out of the capital and into Aden, Hadi's hometown in southern Yemen.
Saleh and Huthi continue to control the capital, where the former president's influence has not waned five years after his reluctant resignation.
By 2016, Saleh had reached a power-sharing pact with the insurgents and ran a parallel government from Sanaa in an alliance insiders and analysts have long warned would not last.
"On both ends, it has been a common enemy... keeping both sides together," said Adam Baron, a fellow at the European Council on Foreign Relations.
"With the expulsion of the Huthis from much of the south, that common enemy has disappeared; thus, it's not shocking that the grudging alliance between southern secessionists and the internationally backed government has devolved into deep tensions."
The common enemy began to come apart at the seams in April, when Hadi fired Aden governor Aidarous al-Zoubeidi and Hani bin Breik, a member of his cabinet.
Both Zoubeidi and bin Breik have historically favoured reinstating southern Yemen's autonomy and went on to announce the establishment of the Southern Transitional Council, with support from local communities and reportedly from the United Arab Emirates, a key player in the Arab coalition.
Saleh for his part is also drawing on his popular reach in Sanaa, which until 2014 had been largely off-limits to the Huthis, confined to the northern Saada province.
Saleh and the Huthis have had a tacit agreement in sharing Sanaa: the ex-president lacks the muscle the insurgents can provide, and Saleh's structural and popular power in the capital is unparalleled.
That delicate power balance may be tested in Thursday's rally, which Saleh has said will be a demonstration of support for "legitimacy" in Yemen.
- 'Mosaic of alliances' -
Analysts say both Saleh and the residents of Sanaa are not happy with the Huthis, who control the defence ministry and military intelligence.
"People are not necessarily coming out in support of Saleh, but in protest against the Huthis," said Yemeni analyst Maged al-Madhaji, director of the Sanaa Centre for Strategic Studies.
"The Huthis are well aware that Saleh needs them, so over the past year-and-a-half they've worked on the military, political and social fronts to try and gain some of the popular support that Saleh has."
This, coupled with reports that Saudi Arabia is looking to cut back on its involvement in the Yemen war, may spell the end of what analyst Baron calls an "alliance of convenience" between Saleh and the Huthis.
Speaking to AFP on condition of anonymity, a source in Saleh's General People's Congress said attempts to mediate this week with the Huthis had failed.
The source also said Saudi Arabia would be happy to see its former ally split from the Huthis but was not yet ready to take Saleh back into the fold.
"Effectively, the conflict in Yemen has never been a two-sided war -- this is something that's been characterised by a mosaic of alliances of convenience from the start," said Baron.
"All things are possible in Yemen, and there have definitely been feelers going out in all sorts of directions for some time now."