(Reuters) - Slogans sprayed across walls in a dusty, working-class district of Khartoum are painted over but still convey their message: Sudan's young opposition activists want to bring an Arab Spring to their country and end President Omar Hassan al-Bashir's rule.
The calls for democracy heard across Arab capitals - toppling autocratic leaders in Tunisia, Egypt, Libya and Yemen since the start of last year - have been late to arrive to Sudan, with demonstrations gathering momentum only since June.
So far, protests have still been small, usually drawing crowds in the hundreds. And they have petered out after the first few weeks in the face of a government response that has included teargas, batons, arrests and - according to Human Rights Watch and Amnesty International - torture.
The government denies using excessive force against protesters or carrying out torture, and dismisses the activists as a handful of agitators with little support among the public. Mainstream opposition parties say they sympathize with protesters, but have been lukewarm at best in support.
Still, a hard core of anti-Bashir activists are trying to spark a popular revolt to end his 23-year rule, devising tactics as they go to overcome the many obstacles to public dissent in the vast, ethnically-divided country.
In interviews with Reuters, underground activists outlined the strategies they hope will eventually bring down the ruling National Congress Party.
"We're not going to make any compromises," a 23-year-old female opposition activist who belongs to the Girifna (We're Fed Up) youth group said in an interview via Skype. "They (the ruling party) have mismanaged the country for 23 years".
A 37-year-old member of Change Now, another of the three main activist groups, speaking to Reuters in a car being driven around Khartoum to avoid surveillance, said: "The alternative we are looking for is a regime that guarantees us dignity, freedom, generous living, expression of our different cultures."
Opposition groups say the triggers that fired Arab Spring uprisings in neighboring countries are present. Many in Sudan's young, growing population are jobless and unlikely to find work in a state grappling with the sudden loss of oil revenues after South Sudan seceded a year ago.
Weeks of protests emerged in June after the NCP imposed cuts in subsidies for fuel and other tough measures to contain an economic crisis brought on by the secession of the South - which cut off Sudan from three quarters of its oil output.
The activists say they are in the fight for the long haul, and accept that they will not topple Bashir as quickly as demonstrators brought down Egypt's Hosni Mubarak last year.
"I really cannot give you a time frame, but I think it's not going to be quick. I really don't think it's going to be Egypt in 18 days at all," said the Girifna activist, referring to the time it took for to topple Mubarak.
Since the start of the demonstrations, security forces have arrested up to 2,000 people, according to a joint report by Human Rights Watch and Amnesty International.
On Tuesday last week eight people were killed in a protest against rising prices in the western Darfur region.
The government is keen to portray the nascent protest movement as out of touch with most Sudanese.
"I feel that those who are protesting - some of them are genuinely protesting over prices," said Ibrahim Ghandour, a member of the NCP leadership team.
"Others are just trying to take advantage of what is expected from opposition parties, to try to turn it into a total uprising against the government. But ... that was not successful."
Some activists say the harsh government response has only reinforced their determination.
"My detention proved to me that the NCP is more afraid than ever," blogger, Maha Elsanosi, who was detained for 20 hours after a protest, said by email.
Diplomats and analysts watching Sudan say the verdict is still out on how much momentum the protests can gain, but with more cuts in subsidies coming there will be more public anger.
"It's hard to say where the protests are going. So far they lack critical mass but if the economy worsens, more people could take to the streets," a Western diplomat in Khartoum said. "The fuel subsidies have been only partially lifted. Prices will go up further."
FREEDOM TWEETS AND GRAFFITI
The protesters have adopted the social media tactics employed in other Arab Spring uprisings, using the Twitter hashtag #sudanrevolts.
Protests are concentrated on Fridays - the traditional day for prayers in Muslim states when mosque-going crowds can be mobilized. Protesters have given the days names, like "Elbow-Licking Friday", a mocking play on the phrase used by officials to dismiss the demonstrations as futile.
The June demonstrations lost momentum under a withering security crackdown and extreme summer heat.
Activists' call for a protest last Friday to mourn the eight killed in Darfur fell on deaf ears. The imam of the Wad Nubawi mosque where the loudest protests had emerged told worshippers not to use it as a launchpad for future demonstrations.
Many Sudanese express reluctance to take to the streets. Civil servant Ahmed Nour, 40, said he believed the government needed to change, but he did not join demonstrations "because I think these youth protests are motivated by anger only".
"The main problem is that there isn't a leadership to lead this change and there's no hope in the known opposition groups," he said, adding that he feared more violence like in Darfur.
Established opposition parties so far show little sign of joining the protests. The main groups have signed a document calling for strikes and sit-ins to topple the NCP, but have yet to bring large groups of their supporters to the streets.
Sadeq al-Mahdi, head of the opposition Umma party and a two-time former prime minister, told Reuters the group's leadership did not oppose the enthusiasm of young activists, but hoped for a negotiated transfer of power which would minimize bloodshed.
"We are more experienced, and we know ... the rules of the game," he said. "Of course youthful expression will be more idealistic ... enthusiastic, will be more revolutionary."
Getting their message across is harder for protest organizers in Sudan than in other Arab states. The reach of Twitter and Facebook is limited in a mostly rural country where only a tiny percentage of people have Internet access. Few Sudanese have access to the satellite news channels that played such an important role in publicizing the Arab Spring elsewhere.
"The most important thing right now is to spread information," the Girifna activist said. Young protesters use graffiti, zooming through poor neighborhoods after midnight spraying messages like "We're fed up with corruption", "Down with military rule", and "Freedom".
"If I spread my message through Facebook and Twitter, there will only be a certain class that will see it, like the students, young people," said one 28-year-old graffiti activist. "Through graffiti, I reach more people."
Security forces paint over anti-government messages within a day or two, obscuring them but also drawing attention to them.
The Sudanese protesters have been in touch online with Egyptian, Tunisian and Syrian activists for tips on how to circumvent government security and galvanize support. Activists say they have found a receptive ear among students at the University of Khartoum and educated professionals like lawyers.
"Sudanese lawyers are among the professionals that have had the most clashes with the regime," a lawyer who joined recent Khartoum sit-ins told Reuters, saying he was motivated to protest by the lack of independence of the judiciary.
Urban activists have also been trying to reach out to people in rural areas: "The most effective way to reach people in the provinces is through their children that work in the city, or students who are in Khartoum," said the Change Now activist.
Girifna tries to counter the security forces by maintaining a decentralized structure, without leaders to round up. Members operate in cells, the Girifna member said. Those who want to join send an email introduction. Cell members vet them online, and make checks at their universities or in their communities.
The safest way is to meet face-to-face, but even that comes with risks, as people fear the presence of plainclothes spies.
"It's all about trust," the Girifna activist said.