A Yemeni man looks at the ruins of his house near the Sanaa airport Tuesday. It was destroyed in an airstrike as Saudi-led coalition warplanes hit Shiite Houthi targets across Yemen overnight. (Mohammed Huwais/AFP/Getty Images)

An unlikely alliance with a deposed dictator appears to have helped Yemen’s advancing Shiite insurgents weather intensifying airstrikes directed at them by a Saudi Arabia-led coalition.

Even as Riyadh expands its aerial bombardment of the insurgents, called Houthis, they are sweeping across the Arabian Peninsula country and threatening to take the strategic southern city of Aden.

According to many Yemenis, analysts and diplomats, a key force behind their gains is coordination with the country’s former strongman, Ali Abdullah Saleh, who ruled for 33 years until an Arab Spring revolt forced him from office in 2012. But Saleh never really left power, and he has retained loyalty from elite army units that did not fall apart in the unrest — unlike the rest of the military — using them and his wealth to assist the Houthis in seizing Yemen’s largest cities, they say.

The partnership has come at great cost, pushing Yemen to all-out civil war, even though few observers think the relationship will last much longer. As president, Saleh was an enemy of the Houthis, launching six brutal wars against them. And many in Yemen see the former president, known for his Machiavellian political maneuvering, as exploiting the Houthi unrest as a way back to power.

“The support from Ali Abdullah Saleh has been crucial, but . . . he will discard them and let them get smashed by the Saudis,” said Abdulqader al-Junaid, a Yemeni political analyst. “Then he tells people that he is the savior and the trusted leader whom they already know.”

For now, the apparent entente has delivered significant blows to forces loyal to Yemeni President Abed Rabbo Mansour Hadi, an enemy of both Saleh and the Houthis. After the rebels toppled his government in February, Hadi fled to Aden and attempted to establish a capital to rival the Houthi-dominated Sanaa in the north. Last week, Hadi, who was a key U.S. ally in fighting Yemen’s formidable al-Qaeda affiliate, left for Saudi Arabia.

In Aden, pro-Saleh special forces units have used artillery and tanks to bombard Hadi loyalists on the northern edges of the city. Their attacks have intensified since the Saudi air campaign started Thursday, killing and wounding scores of people in the port city, Hadi’s last stronghold. Overnight Monday, those artillery strikes killed dozens of people in the city, according to residents.

Ahmed al-Maisari, 47, who is leading a militia in Aden against the rebels, said by telephone that pro-Saleh special forces in the city have been fighting alongside Houthis in military uniform as well as tribal garb.

“You have the teenagers, the tribal guys and then those who are wearing special forces uniforms, even though they have no military training,” he said, adding that their combined forces in the city included “over 30 tanks, many military armored vehicles and Katyusha rockets.”

Support from Iran

Saudi Arabia, the region’s Sunni powerhouse, views the Houthis as a proxy of Shiite Iran. The rebels follow the Zaydi sect of Shiite Islam and have received support from Tehran, although they say this does not include weapons or military training.

However, analysts and diplomats say the Iranian role has been overstated. In part, they say, Houthi advances have been aided by access to vast amounts of weapons, including warplanes, tanks and firearms, already available in Yemen, a significant portion of which was probably obtained from pro-Saleh military units.

“I’m willing to believe the Iranians are making an effort to support the Houthis, but I think that it’s being considerably exaggerated,” said Kenneth Pollack, an expert on Middle Eastern military affairs at the Brookings Institution.

The Houthis benefit from Saleh’s backing, and in return, a Yemeni official said, the Houthis’ religious zeal and battlefield prowess provide the ex-leader with formidable fighters to battle Hadi’s militias and foment general unrest.

“The Houthis believe that God is supporting them,” said the official, who spoke on the condition of anonymity, citing safety concerns. “Their fighters in the south are so young — some are 15 years old — and they actually believe that they went there to die because they think they’re going to heaven. And when Saleh sees them, he thinks of pawns whom he can exploit.”

Ironically, said Ibrahim Sharqieh, a Yemen expert at the Brookings Doha Center, the Houthis became skilled warriors during the wars against them that Saleh oversaw. Since then, they have become more powerful than Yemen’s divided and badly weakened military as well as its fractious tribes, which the rebels have co-opted or defeated.

Saleh, for his part, denies accusations that he has aided the Houthis, and he has blamed Yemen’s instability on Hadi. Saleh could not be reached for comment. Houthi leaders also deny any collusion with him.

Diplomats and analysts say, however, that their coordination was crucial for the Houthi takeover of Sanaa in September. They say Saleh called on loyal officers to stand down, allowing the rebels to swiftly capture the capital.

In November, the U.N. Security Council slapped sanctions on Saleh for threatening stability and undermining a political transition away from his rule. Diplomats and analysts say he has turned to his vast wealth, accumulated during his three-decade rule, to undermine Hadi. A recent U.N. report says he may have amassed as much as $60 billion during that time — a sum roughly equal to Yemen’s annual gross domestic product.

Sectarian discord

A prominent political analyst in Sanaa said the Saudi assaults have begun to stir sectarian sentiment that has pushed Saleh and the largely northern Zaydi tribes, including the Houthis, closer together. Saleh, 73, is a Zaydi Shiite from the north, where there is resentment at the predominantly Sunni south, which used to be a separate country. A civil war in 1994 was won by Saleh’s forces, which defeated southern separatists.

But there are emerging signs of discord between Saleh and the Houthis. Last week, in a televised address, Saleh pleaded for a truce with Saudi Arabia.

Rebel officials were furious.

“Saleh is only doing this to keep his relationship with Saudi and the gulf states friendly, because he wants, above anything else, to protect his personal interests,” said Deif Allah al-Shami, a member of the Houthi political bureau.

Naylor reported from Beirut. Daniela Deane in London contributed to this report.

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