Jihadists affiliated with Al Qaeda are forming alliances with radical Sunni groups in Lebanon, infiltrating the country in a bid to use it as a base for global jihad and to recruit for the civil war in neighboring Syria.

Lebanese army sources say containing the danger is stretching their resources and they are becoming increasingly alarmed at the high levels of jihadist activity, from recruitment to agitation, around the country. Diplomats fear the al‐Qaeda infiltration will feed off—and add to—destabilizing sectarianism sparked by the conflict in Syria.

Retired Lebanese general Hisham Jaber, who still advises the army, says jihadist numbers in Lebanon are growing and now include fighters from the al Qaeda–affiliate Jabhat al-Nusra. “We have many cells, you know, Fatah al‐Islam, Jund al‐Sham, and Al Nusra and similar.”

With the militant Lebanese Shia movement Hezbollah controlling much of the south of Lebanon and the Bekaa Valley, there are few remote areas where jihadists groups can operate freely. The exceptions are the dozen refugee camps housing more than 400,000 Palestinians around the country as well as the countryside around the northern city of Tripoli, which, during this past year, has seen fierce fighting between Lebanese factions on different sides in the Syrian civil war.

The biggest of the camps that were set up for Palestinian refugees fleeing the 1948 Arab-Israeli war is Ain Helweh south of Beirut. Ain Helweh’s population before the Syrian civil war numbered about 80,000 but it now reportedly accommodates 27,000 more people, primarily Palestinian Syrians, adding to the overcrowding and compounding tensions in the camp.

The influx includes hardcore Islamists, Jaber believes, adding to radical elements that were already in the camp before. “Nobody knows when the jihadists will fully wake up. There are thousands of fighters in the camps,” says Jaber, a former top strategist for the army and onetime military governor of Beirut.

What would be in store for Lebanon if—or when—the cells activate was suggested by recent events. Foreign jihadists were involved in fighting in the area near Ain Helweh last month when armed followers of a fiery Sunni preacher, Sheikh Ahmad al-Assir, fired on an army checkpoint, triggering two days of clashes that left 46 dead, including 18 soldiers.

Politician Osama Saad, head of the Popular Nasserist Front, a group aligned with Hezbollah, which is backing Syrian President Bashar al-Assad, says foreign jihadists and Palestinians joined the gun battle. “Some other groups tried to join the fighting against the Lebanese army in order to lift up the morale of al-Assir’s group.” Jihadists from Syria and Yemen were among the gunmen killed in the fighting, say Lebanese army sources.

Jihadists have been present in Lebanon—and especially in the Palestinian camps—stretching back two decades. There was a rapid growth of Salafi jihadist groups in Lebanon following the U.S. invasion of Iraq, and with the tactical cooperation of Syrian military intelligence, hundreds of volunteers from the camps joined the Iraqi insurgency, gaining combat experience and forming ties to al Qaeda.

One of the reasons for the Lebanese army's fears over Ain Helweh and the other Palestinian camps is that they have played prominent roles in the history of violence in Lebanon, having been used in the past by extremist groups. In 2007 the camp at Nahr al-Bared was taken over by the Islamist Fatah al-Islam, triggering a three-month-long siege by the Lebanese army in the most severe internal fighting in Lebanon since the country’s 1975–1990 civil war.

Ain Helweh has seen also its fair share of conflict with clashes between Palestinian groups in 1990 and between Fatah and Islamist groups in 2003 and 2007.

Palestinian leaders at Ain Helweh—a square kilometer of poorly constructed two-story and three-story dwellings and confined streets—play down the presence of jihadists, and radical Sunni Islamists are arguing that most left to fight against President Assad. “There is no al Qaeda or al-Nusra in the camp,” insists Munir al-Maqdah, commander for the Palestine Liberation Organization’s Fatah faction in the camp. “The hard-line Islamists went to Syria to fight there.”

Al-Maqdah, who was born inside the camp, worries that “some people are exaggerating what is happening inside the camps, especially the media” in an effort he believes to stigmatize Palestinians or to manufacture an excuse to strike at the camp. “They say at the end of Ramadan there will be serious fighting, but this isn’t logical unless Israeli elements are conspiring to provoke something. We are doing our best to keep things calm here. We have no interest in getting involved in any fighting in Lebanon.”

But while the Fatah commander plays down the danger, he and the leaders of the other 16 armed factions present in the camp are clearly vigilant and worried and are meeting frequently to try to contain any flare-ups or to prevent the camp from being used as a base for violence elsewhere.

Al-Maqdah says divisions over the war in Syria aren’t helping. “Some are with the [Assad] regime; others are against. I tell people to keep their opinions inside of them, keep it for you, be in sympathy with whoever you want, but don’t create problems here.”

On July 22 all the camp leaders met with Hezbollah representatives in Sidon. “We may have our differences about the peace process. We may disagree over Syria. But we all agree on the importance of security and stability for the camp,” says Abu Ahmad Fadel Taha, the political representative for Hamas, Fatah’s rival. He says that many of the camp’s leaders have known each other since childhood, having been born at Ain Helweh and schooled together. “The friendships help,” he says.

He is less optimistic than his Fatah counterpart that trouble can be contained. Recently a jihadist shot dead a Fatah bodyguard in the camp, and Abu Ahmad says there are problems between the Islamists and Fatah. “Sometimes things get out of line and can’t be controlled,” he says sitting in his bare office in the heart of Ain Helweh, as a ceiling fan whirls overhead, failing to cool the heat of the mid-afternoon.

Abu Ahmad also claims there isn’t a strong al-Nusra presence in the camp but admits the group has been recruiting inside. “There are guys inside in the camp who have this [jihadist] ideology in mind, as there are in Tripoli or Akkar, but always Ain Helweh gets focused on,” he says shaking his head.

General Jaber worries that the Lebanese army is ill-equipped to deal with the growing challenge. “The Lebanese government is really weak, and we only have the army which still has a little prestige and morale. But the army in Lebanon has not been given really what it needs in materiel and personnel.”