In a makeshift boot camp, dozens of Palestinians in black masks and military fatigues charged across a field Wednesday, assault rifles aimed at an invisible enemy.
But for the gunmen from the defeated Fatah Party, the target was clear: the new security force formed by the Hamas-led government.
‘We are going to confront this Hamas unit,’ said one 22-year-old Fatah fighter who only gave his nom de guerre, Abu Satter, and proudly posed with his Kalashnikov rifle.
Hamas also has been busy. Just a few miles from the Fatah camp, Hamas fighters on Wednesday ran drills on how to whisk suspects from a car, cuff and guard them. In another sign of readiness, Hamas recently bought a black market shipment of 100,000 bullets after outbidding Fatah, according to one official involved in the negotiations.
Both sides insist they will not be drawn into civil war. And indeed, since Hamas first challenged Fatah's supremacy two decades ago, there have been local gunbattles between the bitter rivals, but never a full-blown confrontation across the West Bank and Gaza.
However, tempers have been rising sharply in the Palestinian areas since Hamas took power in late March, after its sweeping victory in January parliamentary elections.
In just four weeks in office, Hamas has been backed into a corner.
It can't pay its 165,000 employees because the West has frozen aid and blocked money transfers from the Arab world. The boycott has cut deep: Shops are empty and streets deserted as Palestinians scrape by on dwindling savings.
At the same time, moderate President Mahmoud Abbas has stripped the Hamas government of some of its powers, assuming control of the border authority and the state-run TV and radio.
Initially, the tone between the two sides was civil. Hamas tried not to alienate Abbas, seen as its only shot at international respectability. Abbas, as leader of Fatah, would lose credibility at home if he was perceived as trying to bring down the government of a rival party.
However, wrangling over control of the security forces has laid bare the deep enmity.
The division of authority over the armed forces is murky, allowing for rival claims.
Abbas holds the title of general commander of the 80,000-member security force, which consists of five branches. Three of the branches are under the control of the Hamas-run Interior Ministry, while two report directly to Abbas.
Last month, Abbas appointed a loyalist, Rashid Abu Shbak, as commander of one of the Hamas-controlled branches, the Preventive Security Service. In the 1990s, Abu Shbak had led a crackdown on Hamas, and his appointment was seen by Hamas as a major provocation.
Hamas responded by announcing the creation of a special unit, to consist of some 4,000 of its militants headed by Jamal Abu Samhadana, No. 2 on Israel's wanted list. Abbas annulled the decision, but Hamas refused to back down, and the standoff continues.
Thrown into the explosive mix were Hamas accusations that Abbas is conspiring with the West against Hamas. Abbas ‘is contributing to the siege by trying to withdraw the government's security and financial prerogatives,’ Mohammed Nazzal, a Damascus-based Hamas leader, told the Arab TV satellite station Al-Jazeera.
Fatah leaders countered that Hamas is trying to deflect attention from its financial troubles by attacking Abbas.
In this charged climate, both sides are mobilizing.
On Wednesday, 80 Fatah-linked gunmen performed military drills for journalists on a sandy lot in the southern Gaza town of Rafah. They marched in formation, charged with their rifles, somersaulted over burning tires and pointed rifles at a kneeling, hooded ‘prisoner.’
Their commander, a portly man with the nom de guerre Moatassem Bilaa, said the 80 men were the core of a new unit he hoped would grow to 2,000. He said the unit, formed in response to the Hamas force, would ‘give a tough response to any assault on Fatah members.’
Not to be outdone, Abu Samhadana's men staged a drill a few hours later and a few miles away. Professing loyalty to Hamas' interior minister, one gunman said his job is to protect Palestinians against lawlessness and to fight corruption.
It's hard to predict who would win a full-scale battle.
Gaza is teeming with militants and weapons, a legacy of armed conflict with Israel, particularly the last round from 2000 to Israel's withdrawal in 2005.
Hamas and Fatah each control about 5,000 gunmen in Gaza, intelligence officials say. Fatah may have an edge because it has the support of most of the members of the security forces.
Analyst Moheeb al-Nawaty said the side with the most money would win. It's not the number of firearms that matters, he said, but who can buy the most bullets.
Al-Nawaty said limited armed confrontations in Gaza are likely, but not civil war. In the past month, some 40 people have been hurt in Hamas-Fatah clashes.
In the West Bank, an armed showdown appears unlikely: Hamas remains underground because of the Israeli military presence and is outnumbered by Fatah gunmen.
Flanked by five burly bodyguards, Hamas Prime Minister Ismail Haniyeh assured reporters Wednesday that internal strife ‘is not going to happen,’ a sentiment echoed by senior Fatah politicians.
However, the situation could spin out of control. Al-Nawaty warned that a collapse of the Hamas government would likely lead to chaos.
Hamas spokesman Sami Abu Zuhri agreed. ‘I think a failure of this government is going to create a situation in which everyone is going to suffer,’ he said.
Associated Press writer Ibrahim Barzak contributed from Gaza.