Beirut, Lebanon - The Palestinian refugee camp of Shatila is perilously wedged along one of Lebanon's many sectarian fault lines.
Black Islamic flags adorn the lampposts when approaching this small slum from Sunni strongholds to the north, while expansive Shia ghettoes border the camp immediately to the south.
In recent months, an increasing number of clashes have erupted in and around Shatila, as rival Lebanese factions fight for the loyalty of the socially vulnerable and politically divided Palestinian camps.
The Syrian civil war and rising Shia-Sunni discord in Lebanon are exacerbating the pressure. "These [attacks] are concerted efforts to provoke a response," explained Fathi Abou al-Ardat, secretary for the Fatah movement and the Palestinian Liberation Organisation (PLO) in Lebanon.
On May 12, clashes - described by local residents as the most intense fighting yet - erupted between groups inside Shatila and neighbouring Shia communities. Volleys of gunfire were exchanged for several hours, and the army encircled the camp with armoured personnel carriers.
"We know the Palestinians are divided and some groups are exploiting that to stir things up here. We are not taking the bait, but these groups have to know that if they push too hard we will run all over them like we did in 2008," said Abu Ali, a resident of the Rihaab district, a predominantly Shia neighbourhood on the edge of Shatila.
Palestinian refugees struggle in Lebanon
Although Shatila was founded as a Palestinian refugee camp, many non-Palestinians now live there as well.
Ahmad, a 20-year-old Shatila resident with little education and scant work prospects, reasoned: "Us Sunna reacted strongly and started to boil over when we saw the killing in Syria. This caused clashes with Shia because they are helping with the slaughter of our people there."
Syrian President Bashar al-Assad comes from the Alawite sect - an offshoot of Shia Islam - and the powerful Lebanese Shia group Hezbollah supports Assad.
Like many of his peers, Ahmad has lost faith in the traditional Sunni leadership and places his trust instead with more religiously conservative and combative leaders such as Sheikh Ahmad Assir, who have been trying to garner support from predominantly Sunni Palestinians.
"There are more and more of us prepared to follow Assir," said Ahmad. "More and more people are becoming increasingly religious. Everyone is preparing himself for what may come."
The Palestinian camps in Lebanon consist of basic, overcrowded homes, their people victims of decades of war, neglect and abuse. In Shatila, the buildings are so cramped that sunlight is a rare commodity. The smells of garbage and sewage foul the air and unemployed youth fill the cramped alleys.
"We are seeing increased efforts to recruit from our youth. There is desperation and anger here, so whatever they pay they will find people to say 'yes'. They think we are cheap," said Ayman Zaher, a youth worker in Shatila.
All of the major Palestinian political parties have adopted, and until now managed to maintain, a policy of neutrality in Lebanon regardless of their stance on the conflict in Syria. However, in Ein el-Helweh, the largest and most populous camp in Lebanon, armed groups such as Jund al-Sham, Jabhat al-Nusra and Asbat al-Ansar have found a safe haven under the protective wing of powerful local families.
Their number of followers may not be huge, but their hard-line ideology and links to like-minded movements in Lebanon and Syria make Ein el-Helweh a particularly worrying flashpoint for Palestinians and Lebanese alike.
"There is so much pressure on the camps and they are ready to explode, especially Ein el-Helweh, which could go off before there is a wider conflict in Lebanon. There is so much provocation from the Islamist groups there and I'm not sure if the PLO can keep a lid on it," warned Mutuwalli Abu Naser, a Palestinian journalist and playwright from Yarmouk camp in Damascus, who now lives in Lebanon.
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On the other side, Hezbollah and its allies have also been working to secure the allegiance of Palestinians in Lebanon.
Until withdrawing its troops from Lebanon in 2005, the Syrian government was influential in many of the camps through various Palestinian allies. Since the Syrian withdrawal, Hezbollah has by-and-large maintained Syria's leverage in the camps, even though the stance of several Palestinian groups has shifted since the start of the Syrian uprising.
"Hezbollah works by a very low profile without making noise, because they work with the Palestinians from a security background, not a political one," explained Edward Kattoura, a political analyst at Pursue, a Palestinian think-tank.
Many of the Palestinian camps are located in Hezbollah-dominated areas, especially in Beirut, South Lebanon and the Bekaa Valley.
Recently, Shaker Berjawi - a Sunni "strongman" in Beirut who earned his battlefield stripes in the Lebanese civil war - decided to move the headquarters of his pro-Syrian Arab Movement Party to the edge of Shatila, indicating the importance of the camp's support. While maintaining a local influence over the years, he has switched political allegiances numerous times, and he is now aligned with the Hezbollah-led camp.
"It seems people use us as mercenaries, whether it be for one side or the other. When he opens up his office at the entrance to the camps, he is sending a message that the camps are part of his fight," said Kattoura.
But many Palestinians in Lebanon are driven by nationalist rather than sectarian sensibilities, and the camps may be able to stay out of internal Lebanese conflict.
"Most of Lebanese have a view of the camps as a source of militia fighters and criminals. There is destitution and desperation, it is true, but in fact they are much less sectarian than most of Lebanese society," said Moe Ali Nayel, a Lebanese writer and activist who regularly works in the camps.
"The Palestinians are used like a sacrificial lamb in Lebanon. Lebanese groups like to have Palestinians up front and then the blame can be put on us."
- Marwan Abdulal, Popular Front for the Liberation of Palestine
And the Palestinians' time in Lebanon has cruelly taught them while their loyalty is dear, their blood is cheap, whether it be the massacre at Sabra and Shatila at the hands of Christian militias in 1982, the "War of the Camps" from 1985-87 between the Shia Amal Movement and Palestinian refugees, or the bombardment of Nahr Bared camp by the Lebanese army in 2007.
"The Palestinians are used like a sacrificial lamb in Lebanon. Lebanese groups like to have Palestinians up front and then the blame can be put on us," said Marwan Abdulal, member of the political bureau for the Popular Front for the Liberation of Palestine.
The Palestinian camps can hope to stay detached from the conflict in Lebanon as long as the fighting is constrained to the prevailing pattern of intermittent local clashes and firebrand speeches.
However, should the situation escalate, residents will be hard pressed not to get dragged into the affray.
"It will be very difficult for the camps to stay aside if this descends into a serious fitna [internal dispute]," warned the PLO's Fathi Abou al-Ardat.
"The general atmosphere, the speeches, all of it is setting the stage for a fitna. In reality, it is already here."
Follow Zak Brophy on Twitter: @zakbrophy