By Mohammed Ghobari and Erika Solomon
SANAA/DUBAI (Reuters) - Dancing in circles with decorative daggers, tribesmen seem a festive addition to anti-government rallies in Sanaa. But to some, they signal the potential for Yemen protests to split the country apart.
At Sanaa University, thousands of people who have joined protests camp out together nightly, but they are no unified front: activists in jeans and t-shirts eye the tribesmen in white robes and colorful sashes sitting in separate tents.
"Revolutions around the world are always stolen by others once they succeed, but here, tribal sheikhs (leaders) are trying to steal the revolution before we've even won," said Tareq Saad, a student protester in the capital of Sanaa.
The tens of thousands of protestors taking to the streets daily across Yemen are fighting to bring down a government they see as corrupt and unable to lift them out of crushing poverty.
But tribal sheikhs, seeking opportunities from political favors to electricity and roads, are being assiduously courted by politicians as pressure builds on President Ali Abdullah Saleh to quit after 32 years in power.
The sheikhs are seen as key to securing the tribal backing essential to ruling Yemen, which sits on the strategic shipping lane Bab al-Mandab, where over 3 million barrels of oil pass daily.
So far, tribes have tried to keep the peace. But the scramble for their loyalties could spark new divisions and rivalries that lead to a protracted period of bloodshed.
The government is responding with increasing violence to protests and already more than 30 people have been killed. Some fear a repeat of the crisis in Libya, where rebels have taken up arms against long-time autocratic ruler Muammar Gaddafi.
But this time, conflict would be in a country whose president is a key U.S. ally against the Yemen-based regional wing of al Qaeda, which has attacked Western and Saudi targets.
"This is where it gets dangerous," said Theodore Karasik, a security analyst at INEGMA group in Dubai. "Yemen follows the Libya model... Its leader may not get toppled, and it may get divided among warring factions."
SCRAMBLE FOR TRIBES
In Yemen, a fractious, impoverished Arabian Peninsula state bordering oil giant Saudi Arabia, tribes enjoy stronger allegiances than political parties or any other institution.
"They command more loyalty ... and are armed to the degree that the state can't maintain a monopoly on violence," said Gregory Johnsen, a Yemen scholar from Princeton University. "Tribes are the wings of the state. If different tribes go in opposite directions, Yemen will be unable to function."
Tribes, the most heavily armed in a country which is the second most armed per capita in the world, often clash over water rights and family feuds, adding to concerns of volatility as they wade into the stand-off between Saleh and protesters.
Of particular concern is the escalating competition between Saleh and Hamid al-Ahmar, his main rival. Ahmar, a wealthy businessman and tribal leader eager to climb the political ladder, threw his weight behind protesters to drum up support.
As politicians woo tribal leaders with special favors, they could create a vicious cycle of greed and handouts, creating countless demands and resentments if tribes feel shunned.
Ahmar and Saleh have toured the country offering tribes cars and cash for their loyalty. Some local media reports said the goods on offer were attracting more tribesmen than expected.
"There are hundreds of tribes with individual interests and it will be difficult for Saleh or Ahmar to satisfy them," said a Yemen-based scholar from the Yemen Peace Project blog, who asked not to be named. "If that fails, expect more fighting."
Several tribal leaders have defected from Saleh over complaints that he is not sharing power with those outside his inner circle. At the same time, thousands of young tribesmen, often without approval from their sheikhs, are joining protests.
This younger generation argues it is no different from the students and activists trying to end Saleh's rule peacefully. They too suffer from Yemen's economic plight and feel their leaders don't share the wealth from the favors they receive.
"I've been here since the sit-ins began and I'll stay till the regime falls," said Ahsan al-Hamdani, from the Hamdan tribe. "My salary stopped being paid four years ago and my brother was killed in the Saada war (in the north.) We've lost everything."
Yemen is plagued by intermittent insurgencies in its north and south, and tribal leaders used to send followers to help Saleh crush them. But oil and water resources used to pay off supporters are drying up. Some 40 percent of Yemen's 23 million people live on $2 a day or less and a third face chronic hunger.
"The tribes are hungry," said the Yemen Peace Project's anonymous scholar on its blog. "Tribes are not loyal to any side in particular ... this depends primarily on financial support. Tribal areas suffer from a spiraling economic crisis, malnutrition and near complete neglect in the political scene."
The shared grievances do not alleviate anxieties of activists and youths, who propelled Yemen's rallies into mass daily protests and are wary of their movement being hijacked.
But tribesmen relaxing and singing tribal songs in nearby tents have vowed to keep the peace -- for now.
"We won't resort to violence," said Hussein Ali, from the Madhaj tribe. "But if the government uses violence, of course we will have to defend ourselves."
(Additional reporting by Mohamed Sudam; writing by Erika Solomon; Editing by Jon Boyle)