Sitting in his patisserie in this ancient Mediterranean city famous for its baklava and other sweets, Mr Tarek Abdullah recalled how he was startled when some 200 people chanting Islamist slogans and waving black-and- white flags marched past his shop two weeks ago.
They were demonstrating support for the Islamic State in Iraq and Syria (ISIS) militants in Lebanon's second-largest city Tripoli, which lies 80km north of the capital Beirut.
The city - a bastion of conservative Sunni Muslims in a country where the Shi'ite Hizbollah movement is the most powerful political player - is at the centre of concerns that the Sunni-based ISIS could be looking to take advantage of the country's sectarian split to create unrest in a bid to facilitate ISIS' expansion.
About 54 per cent of Lebanon's population is Muslim, divided equally into strife-prone Shi'ite and Sunni groups. About 41 per cent is Christian, with smaller religious groups making up the rest.
After marching through the main streets under the gaze of Lebanese security forces - who have been specially deployed in the city as part of stepped-up operations since the end of last year - the pro-ISIS rally dispersed.
"There are a lot of people who support the Islamic State in Tripoli... even some soldiers," said Mr Tarek, 57.
Last week, four soldiers appeared in different videos pledging their allegiance to ISIS or the Al-Qaeda-linked al-Nusra Front. Hundreds of Lebanese are believed to have joined ISIS, and the local media has reported the existence of dormant ISIS cells.
In August, the civil war in neighbouring Syria spilled over the border, forcing the army to intervene. The Hizbollah militia also beefed up its presence in some regions.
ISIS declared an interest in expanding into Lebanon in January and analysts said its leader Abu Bakr al-Baghdadi will not stop after seizing vast swathes of territory between Iraq and Syria.
"The Islamic State's familiar slogan, 'Remaining And Expanding', points to an aggressive, expansionist outlook," said London-based researcher Aymenn Jawad Al-Tamimia last month. "There is an assumption the group will seek continual expansion, whatever the cost," he added.
The presence of ISIS fighters is already visible in Arsal, a small eastern town near the craggy Qalamoun mountains. Only a few kilometres away from a section of the Lebanese-Syrian border, which has swung beyond the control of the Lebanese army, this town sees frequent visits from combatants fighting the Syrian army in the mountains.
"Their presence in the town is well known," said a doctor, who added that he had operated on fighters injured in Syria. In August, the Lebanese army was forced to storm Arsal to dislodge ISIS and al-Nusra fighters. After a week of fierce clashes in which hundreds of militants, dozens of civilians and some soldiers died, a ceasefire was declared.
But the militants managed to push the army to the outskirts, and seized 37 members of the Lebanese security forces. Three soldiers were executed and 27 remained captive as negotiations with the government stalled.
The army's raid outraged the mostly Sunni residents of Arsal, showing how sectarian divisions make Lebanon vulnerable to ISIS.
There have been tensions over the support shown by Lebanon's Sunni community and political parties to the Sunni opposition groups fighting in Syria. Shi'ite Hizbollah fighters, on the other hand, have been crucial in the Syrian regime's military victories.
The rift notwithstanding, a tentative national consensus prevails over security issues. Security has been tightened across Lebanon after a series of attacks, suspected to be the work of radical Sunni or Shi'ite groups, left dozens dead last year.
The army, which is made up of all religious groups, operates under a special mandate in Tripoli to quell regular outbreaks of Syria-related violence. It has also deployed more troops to arrest ISIS or al-Nusra members.
Lebanon has stopped ISIS from advancing, said army commander General Jean Kahwaji earlier this month. But he added that ISIS "is relying for support on dormant cells in Tripoli and the northern region of Akkar, in addition to certain political forces in the Sunni community".
Analysts said support for the militants is a consequence of rampant poverty, illiteracy and the presence of Syrian refugees, estimated to number two million.
Beirut-based analyst Abou Zeid said: "A big percentage of these refugees live in the already impoverished city of Tripoli. If ISIS or al-Nusra can mobilise just 2 per cent of this group, it will be a very risky situation."
This article was first published on Oct 22, 2014.
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