By Erika Solomon
ADEN (Reuters) - Under a blazing sun, Yemeni men sling rifles across their backs and drag burning tires to block streets plastered with graffiti: "Death to unity ... the southern revolution is coming."
With security visibly weakened in the nine months since mass protests erupted against President Ali Abdullah Saleh's 33-year rule, many in the southern seaport of Aden openly question the benefit of maintaining unity with the north.
"In Aden, we weren't used to seeing such sights. Gunmen? Burning tires? We were a civilized society," said a 28-year-old hotel worker who identified himself only as Feras.
"The northerners are bringing all their problems to us, and the south is suffering ... It's time for some change. Maybe secession really is the best option."
Aden's alleyways are now awash in paintings of the blue, red, black and white flags of the former socialist republic of South Yemen, whose memory the government had long suppressed -- images of the flag were a rarity in Aden even a few months ago.
A port on the Gulf of Aden, a strategic waterway through which some 3 million barrels of oil pass daily, Aden was the capital of South Yemen until unification with the north in 1990.
Despite efforts by moderates to tone down separatist rhetoric, hard-line leaders of a five-year-old secession movement say their time is nigh.
As unrest grows, Aden is lost in a power vacuum. Sporadic gun battles break out, youths block roads in civil disobedience and bomb attacks blamed on al Qaeda frequently rock the city.
"Our moment is getting closer... We're expecting instability to grow and security to further deteriorate," said Qassim Jibran, of the separatist group called the Peaceful Southern Movement. "We're watching to pick the right time."
Wealthy Gulf states and Western powers have sought to stabilize Yemen for fear of turmoil spilling into neighboring oil giant Saudi Arabia. But a deal to ease Saleh from power has stalled even as challenges to his government grow.
Crushing poverty is spreading and fighting between opposition forces and loyalist troops has budded into proxy wars across Yemen. In recent months, emboldened Islamist militants linked to al Qaeda have seized several cities in the south.
Locals report that armed separatist groups are taking over bits of major highways in more remote areas in the south.
Jibran, a former ambassador for South Yemen who has been imprisoned twice for separatist activities, said "all means" may eventually be used to try to push for secession.
"We seek peaceful change. But there may bloodshed if the two nations cannot go back to what they were."
SOUTH QUESTIONS PROTESTS
Saleh's forces crushed a southern attempt to break free from unity in 1994. Many southerners feel power is in the hands of northern elites who usurp their resources. They say Yemen's diminishing oil wealth is in the south but owned by northerners, and complain they get only token representation in government.
Southerners also lament the loss of an open culture that once permeated the south, and blame this on their conservative northern neighbors. Cinemas are now closed in this craggy mountain city lapped by sapphire waters. Wide avenues crumble along with Yemen's disintegrating economy.
"See this road? It was one of the most beautiful streets in the Arab world -- now look at us," said one elderly man, hobbling down a graying Aden boulevard recently blocked by broken cement blocks and burned-out cars.
The Sanaa government says Yemen's unity is a red line, arguing that southern complaints about unemployment, poverty, land right violations and poor services are shared by the north.
Any attempt by the south to secede would probably lead to violent northern resistance and perhaps another civil war, according to a recent International Crisis Group report.
"Yemen's upheaval presents a rare opportunity to redefine its flawed and failed political compact," said ICG's Group's Middle East and North Africa Program Director, Robert Malley.
"At the same time, it has considerably raised the price of inaction. If nothing is done soon to peacefully address both national and Southern deep-seated grievances, a darker and more ominous chapter could yet be written."
Hopes for economic opportunity and greater regional autonomy quickly pushed southerners into the arms of the anti-Saleh movement in January. Aden suffered the first fatalities of those protests when security forces fired on demonstrators.
But optimism for the protests has slowly ebbed as suspicion grows that the opposition is more intent on settling political scores in the north than addressing southern grievances.
Over the summer, 23 southerners backed out of a national transitional council for the opposition, citing frustrations that southern concerns were left out of the group's agenda.
"I sympathize with the protesters, but I don't think they really think about our problems. The revolution in Sanaa has become a northern revolution," said Majed, who has struggled to find a job in Aden for seven years, a condition he blames on economic mismanagement by the north.
"As for us, the only solution is secession."
Not everyone agrees: "It's a bad idea. It's too late, Yemen has been united politically and economically. It's risky to turn back time," said Sumaya, a 21-year-old university student.
"It's shameful to try to flee now while young people across the country are dying for freedom. I hope we can stay united."
Moderate southerners say the opposition must pay more attention to the south as it negotiates with the government for a power transition. Some southern politicians propose a federal post-Saleh state that gives the south more autonomy.
"Without some innovative ideas it will get harder to keep people convinced of the idea of unity," said Ali Mohammed Ahmed a former parliamentarian and southern leader based in Sanaa.
His colleague Taha Alwan, a professor at Aden University's school of commerce, says many southerners are skeptical the north, a society dominated by tribal loyalties, can develop the civil state southerners say their former country once fostered.
"You feel they will need more work to create that kind of state. Why not let the south, which is closer to that model, have autonomy for itself?" he asked.
Southerners are divided, but separatism is gaining momentum as hopes fade that answers to their grievances will emerge from Saleh's government or its opponents in Sanaa, Alwan said.
"I don't believe people really want secession. But it will be the last resort."
(Additional reporting by Dhuyazen Mukhashaf; Editing by Alistair Lyon)