Gaza City - Night's darkness is broken by a waiting car's headlights on the southern outskirts of Gaza City. A motorcycle appears, and both vehicles travel off-road, their headlights now switched off. The presence of an Israeli aircraft overhead makes the drivers more cautious. They wait half an hour before proceeding to their destination.
Around 20 men, masked and wearing military fatigues, await their arrival. Vegetation hides holes covered with wood. Removing the covers, the men reveal caches of Grad rockets and proudly display their arsenal of rocket-propelled grenades and assault rifles.
They are members of the Al Nasser Salah Al Din Brigades, the armed wing of the Popular Resistance Committees (PRC). In an interview with Al Jazeera, the Brigades' leader, identifying himself as Abu Sayyaf, expressed uncertainty about the current ceasefire between Israel and Gaza's factions.
"Nobody knows what will happen," he said. "Maybe war is coming tomorrow, or maybe a ceasefire. Nobody knows, but we are ready for anything."
Mahmoud, Abu Sayyaf's assistant and number three in the Brigades, is also in attendance and explains the process of ensuring agreement between the various groups within the Gaza Strip. "The ceasefires have rules and we meet with Hamas and make agreements," he said. "If the ceasefire is good for the Palestinian people we respect it, but if it's not, then we will find another solution. When the situation needs something, we will do it. We are always getting ready for the next day."
More rockets launched
The current ceasefire, which ended Palestinian rocket fire and Israel's eight-day bombardment under Operation Pillar of Cloud in November 2012, was brokered by Egypt - then led by Mohamed Morsi.
Recently, the ceasefire appears to be fraying, with the Israeli military and Palestinian armed groups engaged in missile fire and retaliatory strikes.
On February 4, Hamas fighters tasked with enforcing the ceasefire abandoned their positions along the border in protest against an Israeli airstrike on their position. A week later they took up their positions again, as Israel maintained it would continue to hold Hamas accountable for any security threats emanating from Gaza. The force was created in July and sourced from members of Hamas' armed wing, the Izz ad-Din Qassam Brigades.
While Abu Sayyaf claims his fighters are respecting the ceasefire, the Salah Al Din Brigades were reportedly responsible for firing two rockets into Israel on February 14. The attack came after a man was shot dead near the Israeli border while he collected gravel in the Israeli-imposed buffer zone.
The previous week, Abdallah Kharti, alleged by Israel to be a PRC member and involved in rocket launches, was injured in a targeted strike while travelling on a motorcycle, sparking further retaliatory rocket fire from Gaza.
"It's not up to Hamas to say we cannot fire rockets, but if we make an agreement and someone from outside the quorum launches rockets, sometimes it's someone doing it for business - or it's a spy who wants to make trouble," Abu Sayyaf claimed.
Following a relatively quiet 2013, more than 40 rockets have been fired from Gaza since the beginning of this year, according to the Israeli military.
In January, during the visit of Canadian Prime Minister Stephen Harper, Israel's Prime Minister Benjamin Netanyahu warned of further escalation and punitive strikes on Hamas. "If Hamas and the rest of the terror organisation have forgotten their lesson, they will be reminded very soon," he said.
Yuval Steinitz, the Israeli intelligence minister, went further on February 1, and threatened an Israeli invasion of Gaza. "If the drip of rockets from Gaza continues, we will have no choice but to go inside in order to eliminate Hamas and allow the Palestinian Authority to regain control of the Gaza Strip," he cautioned.
Israel: Hamas is responsible
Lieutenant Peter Lerner, a spokesperson for the IDF, told Al Jazeera that Israel recognises the threat to the ceasefire posed by smaller factions - but ultimately considers Hamas, as Gaza's ruling authority, responsible for all attacks emanating from the coastal enclave.
"These groups [like the Salah Al Din Brigades] have the potential to cause death and destruction, but overall we see the situation in Gaza as the responsibility of the Gazan authorities and that is Hamas," he said. "They are challenging the ceasefire and internal strife is keeping the Hamas authorities busy, but our job is to safeguard the border and to respond to security threats. At this time the majority of rockets fired are not from Hamas, but by these types of offshoot groups. They pose a threat but don't have a huge arsenal."
With Gaza's Hamas rulers isolated following the overthrow of Morsi in Egypt and the participation of Hamas' Palestinian rival Fatah in negotiations with Israel, conditions are becoming tougher in Gaza. Amid the continuing Israeli blockade, Egypt's new military-backed government has begun destruction of the network of tunnels that once supplied Gaza with building materials, groceries and weapons. Shortages of fuel, electricity and basic goods are affecting everyday life but Abu Sayyaf is adamant that "militarily we are fine, and nothing has changed".
As US Secretary of State John Kerry continues his diplomatic effort to achieve a two-state solution in the Israeli-Palestinian conflict, Abu Sayyaf said he would not recognise a Palestinian state in the West Bank and Gaza and would fight until Palestine reached from "river to sea" - the Jordan to the Mediterranean - even if it meant fighting against any Palestinian government emerging from negotiations.
"Abu Mazen [President Mahmoud Abbas] is the boss, and he might talk about selling Palestine - but you can't sell Palestine," he said. "Our problem isn't with the Jewish people. We will live with Christians and Jews. All of us are Palestinians, but people are coming from outside to take my land."
"Abu Mazen is crazy," Mahmoud added, shaking his head.
'We focus on the enemy: Israel'
Israel claims the PRC has links with Iran and Hezbollah and is funded, trained and equipped by Hamas. Abu Sayyaf said his men are not interested in domestic politics, only in the group's ultimate aims.
I've taught my seven-year-old son to use a gun and taught him everything about the fight.
"After all the problems between Fatah and Hamas, and the groups in Gaza, we needed the strong people who care about the people, Gaza and the land," he said. "We stay far away from the problems between Hamas and Fatah and focus on the enemy: Israel."
The continuing hostilities between Israel and Gaza's factions place civilians on both sides in the firing line. Mahmoud did not answer clearly when asked whether Israeli civilians were considered legitimate targets.
"We try our best to shoot at the military bases, but if you want to compare us and Israel, Israel attacks children, homes and civilians," he said. "When we started the fight with Israel we used a knife and they used F-16s, so now we have much better guns to fight for our country. And people are not stupid. They know what we do here and for what."
Abu Sayyaf described the motives behind their actions as something fundamental to be passed between generations rather than a mere political act.
"I've taught my seven-year-old son to use a gun and taught him everything about the fight," he said. "My father taught me about Palestine and freedom, and I do the same for my son. You have to fight for your country and live a good life."
Follow Nigel O'Connor on Twitter: @nigel_oconnor