By Mariam Karouny
TRIPOLI, Lebanon (Reuters) - Two rival communities are preparing for war in Lebanon's northern coastal city of Tripoli and the frontline in their conflict is a street called Syria.
In the Sunni Muslim district of Bab Tebbaneh, Syrian rebel flags flutter from buildings, declarations of support for the one-year uprising against Bashar al-Assad.
The neighboring Jebel Mohsen area is home to Tripoli's defiant Alawite minority - from the same sect as Assad - who display their loyalty with pictures of the Syrian president.
Bullet holes scar buildings in both districts, reminders of conflict which date back nearly four decades and which flared again last month in street battles between fighters firing automatic rifles and rocket-propelled grenades.
Two people were killed in that confrontation before the army was deployed to restore calm, reinforcing fears that the turmoil in Syria, which has already polarized Lebanese politicians and religious communities, may spark wider violence in the country.
Along Syria street, the dividing line between the Sunnis of Bab Tebbaneh and Alawites of Jebel Mohsen, banners supporting Assad flap alongside posters demanding his downfall.
On Fridays, when frictions often rise after Muslim prayers, soldiers deploy in force in the street to prevent further clashes. Armored personnel carriers are stationed in the area throughout the week.
"When the army leaves, people will kill each other ... It will be war," said a Sunni Muslim fighter from Bab Tebbaneh who gave his name as Abdullah.
LEBANON WAR "ISN'T OVER"
Tensions between Jebel Mohsen and Bab Tebbaneh date back to the early years of Lebanon's 1975-1990 civil war, when Assad's father Hafez al-Assad sent troops into Lebanon, a military presence which was to last until 2005.
Alawites in Tripoli sided with the Syrian forces, while the city's Sunni Muslims backed the Palestinian militants fighting Assad's troops.
"The (civil) war ended but it is not over here," said Waleed, a Sunni Muslim fighter and community leader. "The people of Bab Tebbaneh suffered the most from the Syria regime."
"At least 86 people from here are still missing since the 1980s. They disappeared because of the Syrian regime and we don't know if they are dead or in prison."
"Now the wounds have reopened," he added, his message reinforced by fresh pictures of residents, missing for 30 years, pasted on the walls of Bab Tebbaneh against a background of rebel Syrian flags.
Zakaria al-Masri, imam of a mosque in the Qebba district where anti-Assad protests take place most Fridays, said people had a duty to support the overwhelmingly Sunni Muslim uprising in Syria after a year of unrest in which the United Nations says 8,000 people have died.
"Syrian people are facing injustice. It is important to stand by those facing injustice," he said at a demonstration earlier this month where people waved rebel Syrian flags and children painted anti-Assad slogans including "Freedom" and "Leave" on their foreheads.
Alawites in Jebel Mohsen, a hillside district overlooking the Mediterranean city, counter that the hostility to Assad has come from an increasingly hardline current of Sunni Islam which they say is taking hold in their city. They say they are well armed and ready for a showdown.
"We have noticed how extremism is spreading and nobody is criticizing it," said one man at a cafe in a poor district of Jebel Mohsen. He said some moderate Sunni sheikhs in Tripoli had been replaced by more conservative clerics, adding he saw more men with long beards and short dishdasha robes - signs of extreme religious piety - some of whom did not speak Arabic.
"We are a minority. Nothing will protect us but our weapons," said another man, who said that any conflict in Tripoli would spread to the capital Beirut and the Bekaa Valley.
"We have plenty of weapons and we are buying - heavy and light weapons, all is here," he said.
GUNS IN EVERY HOUSE
Weapons are a constant feature of conversation in the tinder-box city, and are rarely out of sight.
Speaking to a reporter in his home, Waleed proudly held his M-16 assault rifle, while his son showed off a Kalashnikov, saying they were stocking up on arms for the war they expect will erupt in Tripoli.
"We are buying guns to defend ourselves. Each house has guns depending on the number of men in the house," said the 52-year-old father of three, who says his own father was killed by Syrian forces.
His two sons and daughter are all trained to use a gun.
"Ten-year-old boys can use guns here. All men teach their sons how to use weapons. Even our women, we teach them".
"I know people who sold their televisions and gold just to buy weapons," he said. "When we are living in a security vacuum it is only natural that we protect ourselves".
A Tripoli resident called Munir said the bloodshed in Syria, where Assad's forces bombarded the rebel Homs neighborhood of Baba Amro into submission last month, had brought back Lebanese memories of their own civil war.
"What is happening in Syria has repercussions here. When a son of Bab Tebbaneh sees what happens in Syria he is reminded of what happened in the 1980s," he said, speaking at a cafe near the Sunni Muslim district.
"People lived through the same shelling and same massacres."
SPARK FOR CONFLICT
Although both sides say they are ready for a fight, no one will predict when the spark for a conflict might be struck.
"Definitely there will be a battle here but the question is for what purpose," said Waleed, who estimated the Alawites had about 1,000 to 2,000 fighters, while the Sunnis had 5,000. "Everyone is waiting for the right moment."
Most political leaders in Lebanon, from Sunni Muslim Prime Minister Najib Mikati to Shi'ite Hezbollah leader Sayyed Hassan Nasrallah, have sought to prevent the Syrian crisis from spilling over into its smaller neighbor.
But the uprising has laid bare the country's divisions, with Nasrallah backing Assad and others, including Druze leader Walid Jumblatt and former Sunni prime minister Saad al-Hariri stepping up their condemnation of Assad's crackdown.
"Bab Tebbaneh and Jebel Mohsen are the weakest link in the country, but to ignite it requires a decision," Waleed said.
One Alawite resident, referring to the high levels of deprivation in Tripoli, said it was no accident that poverty was so widespread in the port city.
"We are left here as poor people so that when they need fuel for any war they can use us," he said, standing near two mosques, one Sunni and another Alawite, both pockmarked with bullet holes.
Another supporter of the Syrian leader, sitting in a car playing songs praising Assad, said Alawites were brought up to fight "to the end".
"When a child is born we do not bring him gold or sweets. We bring him a gun. This is his gift because he will be a fighter."
He smiled, and added: "Let them try to fight us".
(Writing by Dominic Evans; editing by Janet McBride)