By Mohammed Ghobari and Noah Browning
SANAA/DUBAI (Reuters) - Emirati tanks heave across southern Yemen's stony wastes and Apache (NYSE:APA) helicopters from a Saudi-led coalition, dubbed "black genies" by local media, rule its skies, helping fighters loyal to the exiled government win the initiative against an Iran-allied militia.
The advanced weapons deployed by Gulf Arab states have powered the local fighters into territory controlled by the Houthi group, reversing the tide in a civil war linked to a regional power struggle between Sunni Muslim states and Iran.
But some Yemenis now fear that the coalition's desire for a knock-out blow on the battlefield may trump chances of a compromise that could piece back together the shattered state and spare the ancient capital Sanaa from a devastating showdown.
"Everyone's afraid that the war will soon arrive," said Mohammed al-Awadi, a storekeeper in the city, chewing narcotic qat leaves, a national pastime and a welcome distraction from the problems which rack the nation.
"People are hoarding food or else fleeing to the countryside and there are Houthi fighters everywhere in the streets."
Yemen's foreign minister in exile has upped the ante, saying the war may soon end with the violent downfall of the Houthis' leader and their ally, ex-president Ali Abdullah Saleh.
"As for the deposed president, I'm sure he'll go through something awful. Either he'll flee to another country or meet Gaddafi's fate, killed in a ditch or basement. Abdul Malik al-Houthi, I think he'll flee to Iran or some mountains that will then turn into a combat zone," Riyadh Yaseen told the Saudi newspaper al-Okaz.
Forging an unlikely alliance, Saleh and the Shi'ite Muslim Houthis put aside years of enmity to seize the capital in September and march on the southern city of Aden in March, triggering the Saudi-led intervention and hundreds of air strikes.
The kingdom feared the Houthis' ties to Tehran meant its southern neighbor would fall under Iranian influence, but the militia denies being beholden to the Islamic republic and says it is trying to save Yemen from jihadists and Western imperialism.
Battle lines barely budged after war erupted on March 26, but Saudi Arabia and the United Arab Emirates bided their time in training and arming the southern fighters loyal to the exiled government who ejected the Houthis from the port last month.
Though advances toward the capital have been made on three fronts, winning the northern home turf of the Shi'ite militia may prove a tougher fight for the mostly Sunni opposition.
"(There is) a need to ensure that there isn't a reckless military momentum that develops which ignores the obvious dangers of pushing on," a diplomat in the Gulf who focuses on Yemen told Reuters.
"The coalition's military objective of correcting the balance on the ground in such a way that political talks could resume with the government in a position of strength has been achieved. It's therefore important to ... convert the military momentum into political momentum."
NATION-BUILDING
For the Gulf Arabs, bristling at Iran's role in sectarian wars rocking Syria and Iraq, the gains in Yemen prove they can seize their collective destiny from their arch-rival, even as their ally the United States has reached a nuclear deal with the Islamic Republic last month.
"Success of Arab coalition led by Saudi Arabia significantly alters political tools in region. Our ability to influence our world is now tangible," Anwar Gargash, UAE minister for state for foreign affairs, tweeted this month.
"Compare with other crises lately. Arabs taking charge for once," he said.
But while winning moves on Yemen's battlefield and the region's strategic chessboard have heartened the Arab world's richest countries, they face their first test in nation-building in one of one of its poorest and most dangerous.
A branch of the ultraviolent Islamic State group has cropped up in Yemen and launched bombings against the Shi'ites, raising the long distant specter of a bloodbath among religious groups.
Months of combat with the Houthis have united fighters from al Qaeda's Yemen branch, the world's deadliest, with tribesmen in the country's rugged backcountry, boosting the militants' legitimacy and room to plot attacks on the West.
Meanwhile residents of Aden, ruined by months of Houthi shelling, say they still struggle with shortages of electricity and power.
Disparate militias patrol the streets in the absence of police and a functioning government, and the power vacuum and uncertainty may yet follow their progress northwards.
"The level of damage and the humanitarian need is very high in liberated areas. The Yemeni state was destroyed by the Houthis and Saleh, and the challenge is for now greater than our abilities, though we are working with our Gulf partners to meet it," senior Yemeni official Rajeh Badi told Reuters.
Badi said the exiled government was making diplomatic efforts to avoid a final showdown, but as loyalist forces continued their push, the Houthis could be convinced to back down - a high-stakes wager which could determine the fate of the country and the Gulf's ability to pacify it.
"We hope the Houthis and Saleh will learn the lessons from their losses and withdraw ... as they are pushed back more, the concessions they are willing to make will increase."
(Additional reporting and editing by Angus McDowall; Editing by Giles Elgood)