The remains of an Israeli military hilltop outpost overlooking Gaza's second-largest city have been cordoned off by razor wire and fortified with sandbags.
The custodians of land that was part of the Israeli Gush Katif settlement block until disengagement last year are not Palestinian police but armed squatters from the Abu Reesh Brigades, a militia affiliated with President Mahmoud Abbas's Fatah Party. And the militia's frayed blue and magenta banner fluttering quietly in the breeze is their deed of ownership.
"We just took this place," says Abu Harwun, a militia commander who uses a pseudonym. "Until now there is no authority in Gaza."
Amid a yawning vacuum of power despite Hamas's victory over Fatah in January's election, Gaza's mosaic of militias are expanding a network of improvised bases on empty land - much of it in the abandoned Jewish settlement - in the name of the Palestinian uprising against Israel.
But as Mr. Abbas and the new Hamas-led Palestinian cabinet jockey for control of a government gripped by financial insolvency, the encampments are seen as yet another troubling sign that Gaza may be headed for a civil war.
Highlighting the growing tension, Palestinian gunmen from Fatah's Al Aqsa Martyrs Brigades briefly took over the Palestinian cabinet building in Ramallah Thursday, protesting the Hamas government's refusal to meet their demands for perks and new promotions, the Associated Press reported.
"People are scared that this power struggle between Fatah and Hamas could turn into a violent struggle between the two," says Eyad Saraj, a human rights activist who heads the Gaza Community Mental Health Program. He says the political rivalry is liable to devolve into a free-for-all among rival militias and regionally based Gaza clans.
"If everyone is taking a piece of land and making it his base, we fear that Gaza will be turned into a feudal system in which these military leaders will take an area and declare it their own territory."
The Gaza encampments function as part recruitment center and part training ground for firing weapons and rocket-propelled grenades. The Abu Reesh commander says his camp "raises the hope" of teenagers recruited fresh out of high school so they can be prepared for the "military life."
Along a beach-front strip on the northern outskirts of Gaza City, the camps have been set up side by side in a succession of yellow, green, black, and red flags that advertise Fatah, Hamas, Islamic Jihad, and the Popular Front for the Liberation of Palestine, respectively.
In recent weeks, militants have stepped up recruitment and the number of camps is growing, says one Palestinian Authority official.
"First of all, it shows that you're in the street - a sign that 'we are here' as a part of the resistance," says Tawfik Abu Khoussa, a former Interior Ministry spokesman who now works for the president's office after Hamas took control of the entire Palestinian cabinet.
"This kind of thing is making society more armed, and maybe these training camps will be part of a civil war. If there is a little problem on the street, they won't start fighting with their hands, they will start fighting with their guns," he says.
Although the new Hamas government has pledged to bring order to growing lawlessness in the West Bank and Gaza, militants see Hamas's support for continued violence against Israel as a green light to set up more camps, even if they haven't gotten authorization.
The sites are also a launch pad for the rocket attacks into Israel that have spurred a week-long barrage of retaliatory shelling that killed 17 Palestinians and stirred frustration with the new government.
Some see an ironic role reversal in the fact that Hamas militants have remained silent in the face of Israeli shelling while Fatah gunmen have taken the lead along with Islamic Jihad in launching the homemade rockets into Israel.
If Hamas suicide bombers once played spoiler to the Fatah-run government that sought to calm tensions with Israel and resume peace talks, now it is the Fatah-allied brigades that have turned up the heat on the Islamic militants as they try to grapple with diplomatic isolation.
The thud of artillery shells has become an unnerving background noise of daily life in Gaza over the past week, and the simmering hostilities have stoked public criticism of Hamas's neophyte government for failing to rein in the rocket launchers.
At an empty base belonging to Fatah's Al Aqsa Martyrs Brigades just outside the entrance of the former settlement of Neve Dekalim, spray-painted graffiti welcomes visitors to "The Camp of the Martyrs."
A young sentry calling himself Abu Hassan says that the gunmen at the camp had gone into hiding because of the Israeli shelling. When the PA decides to develop the land, the militia would go elsewhere, he says.
But, when pressed whether the Aqsa group would be willing to evacuate the outpost at the request of the Hamas Interior Minister Said Siyam, the young guard demurred. "It's not the responsibility of Said Siyam. It's the responsibility of my leadership."