TRIPOLI, LEBANON // Rival militiamen have been settling sectarian scores over the past week on this city's gritty streets.
Bullet holes riddle storefronts as the crackle of machine guns sends bystanders scurrying for cover. It has been, Tripoli residents say, some of the worst fighting here in years.
From their neighbourhood stronghold of Bab Al Tabbaneh, ultraconservative Sunni Muslims known as Salafis trade gunfire with the Alawites, followers of an offshoot of Shiite Islam, who live in the adjacent area of Jebel Mohsen.
The violence closely mirrors the rebellion in Syria, which pits a largely Sunni-led insurgency against the Alawite regime of President Bashar Al Assad. Bab Al Tabbaneh's Sunni residents fly the flag of Syria's opposition, while the pro-Assad Alawites of Jebel Mohsen have plastered homes and businesses with posters of the Syrian autocrat.
For many here, the battles strongly suggest Syria's uprising has aggravated Lebanon's tinderbox of competing religious communities.
But the immediate concern of Jebel Moshen resident Rima Haddad, 53, is avoiding the snipers perched on nearby apartment buildings.
"We're imprisoned in our homes for most of the day because if we go outside, we'll just get shot at," Mrs Haddad said while standing next to a convoy of Lebanese soldiers.
They were deployed on Tuesday to halt the fighting that has killed at least a dozen and wounded hundreds more.
The clashes were triggered by the arrest on May 12 of a little-known Islamist, Shadi Al Mawlawi, in Tripoli. It prompted street demonstrations by hundreds of Sunnis, who form the majority of the city's more than half-a-million residents.
The protests quickly escalated into an armed confrontation between fighters in the Bab Al Tabaneh and Jebel Mohsen neighbourhoods, divided by a narrow thoroughfare named Syria Street.
Supported with money and, some say, weapons by Damascus, militiamen from the Alawite Arab Democratic Party (ADP) wield rocket-propelled grenades and machine guns.
Salafi gunmen targeted Jebel Mohsen's 60,000 residents with semi-automatic sniper rifles, supplied, many here say, by Gulf Arab states.
Such quarrelling over Syria is certainly not new. Mutual resentment has festered ever since Syrian forces invaded during Lebanon's 15-year civil war, which ended in 1990, allied with Alawites and clashed with Sunni militias in Bab Al Tabaneh.
But now the increasingly influential Salafis of Bab Al Tabaneh, who consider their neighbours apostates, say the fight is to defend Syrian rebels. In turn, Lebanon's small minority of Alawites, primarily living in Jebel Mohsen, portray Bab Al Tabbaneh's Salafis as radical Islamists.
"We're defending ourselves, the Lebanese people and the Syrian people against Al Qaeda," said Abdul-latif Saleh, a spokesperson for Rifaat Eid, who heads the ADP.
What does seem clear, according to some analysts, is the role that both sides play in the regional competition between the Syrian government and countries such as Saudi Arabia and Qatar.
To shore up its Mediterranean flank, Damascus sees Lebanon's Alawites as a useful buffer against Tripoli's Sunnis, said Ahmad Moussalli, professor of political science and Islamic Studies at the American University of Beirut. Gulf states, on the other hand, see the city's Salafis as leading a new front in the 14-month uprising to topple the Assad government.
"The Saudis and Qatar want to turn the north into a corridor for the Syrian opposition," he said, citing reports of increased arms flows on multiple fronts, including Tripoli, to rebels in Syria.
Last month, Lebanese authorities intercepted a Tripoli-bound cargo ship carrying more than 100 tonnes of heavy armaments reportedly destined for Syria's opposition.
"We have to understand that the north of Lebanon has become part of the Syrian-Saudi conflict," Mr Moussalli said.
The leader of Salafi fighters in Ban Al Tabbaneh, Abu Al Bara', a nom de guerre, did not deny the help from Gulf countries.
But for the bearded imam of a local mosque, the fight seemed as much about highlighting frustration with Lebanon's Sunni leadership as it was a show of solidarity with Syrian rebels.
"We are tired of our corrupt politicians in Beirut," Abu Al Bara', 39, said from his apartment on Syria Street.
Misbah Ahdab, a former parliamentarian from Tripoli, acknowledged the problem radicalism played in the recent flare-up in fighting between Jebel Mohsen and Bab Al Tabbaneh. But an even bigger issue was the failure of Beirut's politicians to force the military to strip the city's militias of their firepower.
Such efforts have been stymied because of political squabbling between competing groups, including the powerful and heavily armed Shiiite movement, Hizbollah, he said. That, in effect, made Tripoli's militias far more useful tools for meddling in Syria's affairs, and vice versa, he said.
"There's no doubt these are proxy battles by bigger powers - but these proxy wars are easy to wage when the state doesn't want to the disarm militias that are allowed to fight whenever they want," Mr Ahdab said.