TRIPOLI, Lebanon— Sheik Nabil Rahim is jolted by what he hears nowadays from angry teenagers in the poor neighborhoods of this city, the country’s second-largest and the hub of its Sunni Muslim community.
“They say we want Islamic State, the Islamic State is coming—but they have never actually spoken with someone from Islamic State,” said Mr. Rahim, an influential Salafi preacher who himself was imprisoned for years on terrorism charges.
Support for other, less radical, Islamist movements has withered, he added, “because they don’t have all those great victories.”
In Tripoli’s Bab-el-Tabbaneh neighborhood, where an Islamist militia already holds sway and where Lebanese army checkpoints come under gunfire or grenade attack almost nightly, support for the Sunni radicals of Islamic State is clear. Giant murals of the militant group’s black-and-white flags are painted on the sides of buildings off the main thoroughfare.
“Something scary has happened in Syria and Iraq, and now something strange has come to Tripoli,” said shopkeeper Sam Omar, whose wife’s cousin—a soldier—was killed in one of the recent Tripoli attacks.
Separated from Lebanon by strongholds of the Syrian regime, Islamic State is not about to take over Tripoli anytime soon.
But it is posing an insidious threat from within. Among Lebanon’s Sunni community—27% of the population, according to the Central Intelligence Agency—the violent movement is finding fertile ground in the same kind of resentment and alienation that propelled its meteoric rise in Syria and Iraq.
“There is injustice here. There is marginalization,” said Mouin Merheby, a Lebanese parliament member and a vocal defender of the Sunni community in Tripoli and the country’s north.
Lebanon’s devastating 15-year civil war ended in 1990 with a deal that was supposed to empower the Sunnis, by strengthening the prime minister, who is by arrangement a Sunni, at the expense of a president, a Christian.
But the assassination of former Prime Minister Rafik Hariri in 2005, blamed by many of his supporters on Syria’s regime and its Shiite ally Hezbollah, has deprived Lebanon’s Sunnis of a moderate, charismatic leader—pushing many toward the Islamist alternative.
Since then, Lebanon’s Sunnis have watched with dismay as Hezbollah, which maintains a potent armed wing, has come to dominate the Lebanese state, especially after showing its muscle to briefly take over a key Sunni neighborhood in Beirut in 2008.
In a region now consumed by a sectarian conflict, this sense of injustice was inflamed by the fact that Hezbollah has directly intervened in the Syrian civil war, helping Syrian President Bashar al-Assad ’s regime fight the Sunni rebels with whom many Lebanese Sunnis sympathize.
That intervention has also brought the war into Lebanon, with Syrian rebels attacking the Lebanese army, which they view as allied with Hezbollah, in the mountainous Arsal area along the border in August. These rebels, some of them affiliated with the Islamic State, still hold dozens of Lebanese troops hostage, security officials say.
“There is a big problem: the situation is imbalanced,” said Nohad Machnouk, the interior minister in Lebanon’s coalition government and one of its leading Sunni politicians. “The Sunnis feel as if Hezbollah in Syria is fighting them. They always feel that they are not allowed to do so and so and so, and on the other hand other parties, like Hezbollah, can do all these sos.”
Those who translate this frustration into embracing the Islamic State “are still until now very few,” Mr. Machnouk said in an interview. “I insist on saying until now. It depends on how the situation is going to be in Iraq and later on in Syria… We are part of the region and we are now in the Syrian war and in the Iraqi war.”
Aiming to prevent the violence from spreading in Tripoli, the Lebanese Army has set up a string of checkpoints in the city, using blast walls to shield second-hand Humvees supplied by the U.S. and its own aging M-113 troop carriers. The army’s main target is a militia run by Shadi Mawlawi, an Islamist in his late 20s, that operates out of Bab-el-Tabbaneh.
Mr. Mawlawi, who was detained by Lebanese security services during a roundup of local Islamists in 2012 and released following deadly protests against the detention, took over a mosque in Bab-el-Tabbaneh this year with dozens of armed supporters and turned it into a base from which they control the area.
A court sentenced Mr. Mawlawi to death in absentia this month for his alleged role in an August 2014 attack on Lebanese troops. Mr. Mawlawi vacated the mosque in recent days and went into hiding, but he and his gunmen still control the area, officials say.
Lebanese security officials say Mr. Mawlawi’s militia, initially little more than a neighborhood gang, is now connected to Islamic State-linked militants in Arsal.
Mr. Mawlawi couldn’t be reached for comment. As recently as September, he denied being part of Islamic State on Lebanese TV.
Bab-el-Tabbaneh residents say recruits are offered as much as $1,500 a month to join—a lucrative prospect in the ramshackle area.
“While the number of armed men here is small, poverty creates an environment in which they can thrive,” said Toufic Dabbousi, head of the Chamber of Commerce of Tripoli and North Lebanon. “None of the Lebanese governments has had any faith in the city, or did much to develop it.”
Islamic State—landlocked so far—seeks access to Tripoli because seizing the port city would give it a much-needed outlet to the sea, said Brig. Gen. Ali Kanso of the Lebanese army. That will not happen, he assured, because Islamic State—known here by its Arabic acronym Daesh—lacks popular appeal among the Lebanese.
“The ideas of Daesh are not accepted by the people in Tripoli,” Gen. Kanso said. “Our people are sophisticated and educated. Who can approve of decapitations and selling women to slavery in the 21st century?”
To a point, that is certainly true. Even though many people in Tripoli resent the Lebanese Army’s cooperation with Hezbollah, the military deployment has been by and large welcomed.
“If Daesh comes here, I will myself pick up a gun and join the army,” said Waleed Danawi, an unemployed electrician from Bab-el-Tabbaneh. Umm Fadi Sidawi, a toothless grandmother who overheard the conversation, broke out in chanting: “God bless the army, we all love our army.”
But all that support depends on the extent to which the army—and the Lebanese state in general—manages to avoid being sucked into the deepening vortex of the Syrian war. If regional violence escalates, sectarian identity here—just as in Syria or Iraq—may well trump for many their apprehensions about Islamic State’s brutality.
“Though people here are unhappy, most of them are not going to side with Daesh against the army,” said Mr. Rahman, the Islamist preacher who now helps operate a Qatari-funded religious radio station in Tripoli. “But if Hezbollah comes here, they will definitely side with Daesh against Hezbollah.”