Khan Yunis (Palestinian Territories) (AFP) - In a "tunnel city" under the sandy soils of southern Gaza, Palestinian militants are preparing for the next conflict with Israel, as tensions in Jerusalem threaten to escalate.
The underground passageways leave no trace on the surface.
But in a wooded area near Khan Yunis, seven masked men in military fatigues carried a collection of machine-guns and grenade launchers into a tunnel entrance discretely tucked into the foot of a small hill.
The fighters wear headbands of the Al-Quds Brigade, the armed branch of Islamic Jihad which is the second-largest armed faction in Gaza, after the Hamas Islamist movement that rules the territory.
The tree branches covering the hole reveal a narrow passageway walled and topped with concrete blocks.
Complete with electric lights, a ventilation system and telecoms cables, the tunnels also have small rooms for storing weapons and ammunition.
An Islamic Jihad official told AFP during a media tour that the movement has both defensive and offensive tunnel systems.
The latter "is used for taking Israeli soldiers captive, repelling Israeli ground offensives and carrying out various field operations", said the commander.
As he was talking, he received a radio alert of a "security incident" east of Gaza City -- a false alarm.
Last May during an 11-day war, Israel launched multiple strikes against what it called the "Gaza Metro", a network of tunnels that had allowed fighters to move around without being spotted by Israeli drones and to take Israeli targets by surprise.
KFC and rockets
Residents of Gaza, a cramped, besieged coastal territory home to 2.3 million people, have long experience of using tunnels since 2007, when Israel imposed a crippling blockade in response to Hamas seizing power in the Strip.
Smugglers stablished a network of tunnels on the border with Egypt, enabling them to import everything from desperately needed household goods to cars and even Kentucky Fried Chicken -- as well as weapons.
In recent years, Egypt has destroyed most of those tunnels.
Israel, for its part, has boosted its forces around the territory, reinforcing a hyper-secure barrier with an underground steel wall it hopes will prevent tunnels reaching into Israeli territory.
Israeli commanders fear militants could use such tunnels to seize Israeli personnel or civilians for use as bargaining chips in prisoner exchanges.
But even if Islamic Jihad's tunnels cannot reach Egypt or Israel, they are still "a strategic weapon for the resistance", said Al-Quds Brigade spokesman Abu Hamza.
"We will let the days and the battles to come do the talking about the ability of the resistance to break through this so-called (Israeli) barrier," he told AFP.
Weeks of deadly violence including angry demonstrations and a police crackdown around Jerusalem's Al-Aqsa Mosque have prompted Islamic Jihad to threaten an escalation.
After two deadly attacks in the coastal Israeli city of Tel Aviv, the Israeli army carried out large-scale raids in the West Bank, notably the Jenin area from which the attackers hailed.
Those operations sparked intense firefights which killed several fighters from Islamic Jihad, which is supported by Israel's nemesis Iran.
And on Monday evening, a rocket was fired from Gaza into Israel, prompting an Israeli air strike against a weapons factory.
No faction has yet claimed responsibility, but the incident -- the first of its type since January -- heightened fears of a further escalation.
A couple of hours' drive from Gaza City, "the tunnels have been repaired and the rocket stocks have been replenished" since last year's war, according to Abu Hamza, who praised Iran for its support.
The spokesman would not be drawn on the size of the organisation's tunnel network or how many fighters it has.
But another Al-Quds Brigade source, who asked not to be named, said it had "a large number of offensive tunnels that stretch deep into (Israel) and are linked up to a system of drones".
He said the group also had rockets capable of reaching the whole of Israel.
A short distance from one of the tunnel entrances, a group of fighters sit chatting under the trees.
"We've received instructions to mobilise and be on high alert to defend the Al-Aqsa Mosque and Jerusalem," said one.
"The rockets are on high alert and we're waiting for the leadership to decide."
