Hamas, the militant organisation that seized control of Gaza from the Palestinian Authority at gunpoint 18 months ago, can mobilise 15,000 armed paramilitaries to face an Israeli onslaught.

Hamas, the militant organisation that seized control of Gaza from the Palestinian Authority at gunpoint 18 months ago, can mobilise 15,000 armed paramilitaries to face an Israeli onslaught.

Of these, about 1000 are Iranian and Hizbollah-trained commandos from its military wing, Iz al Din al Qassam - the grandiosely-named "Tip of the Spear". Palestinian sources say Iz al Din troops undergo rigorous instruction, including in the use of advanced anti-tank weapons and in urban warfare in the warren of alleyways that intersect Gaza's sprawling concrete jungle.

There are also another 14,000 Hamas enforcers, the Kalashnikov-toting militiamen who maintain the organisation's grip on the 1.5 million population crowded into the Gaza Strip, and hunt down rival Fatah political opponents.

This group has basic training for using assault rifles and rocket-propelled grenades, but has few military skills beyond providing a pool of cannon-fodder in support of Iz al Din.

Israeli intelligence sources say Hamas has used the six-month ceasefire to replenish its stocks of weapons and ammunition via smugglers' tunnels under the Egyptian border and to dig a network of bunkers and trenches amid the urban sprawl to meet any ground assault.

Other militant factions, such as Islamic Jihad, can be expected to co-operate in the event of an engagement with the Israelis, adding up to 2000 fighters to the mix.

Two Popular Resistance Committee factions are likely to subordinate themselves to the organisation in a war with Israel.

Analysts believe Hamas currently has a stockpile of more than 1000 home-made Kassam rockets ready to be launched against targets deep inside Israel.

Many have been manufactured inside the Strip, while longer-range projectiles have been supplied by Hizbollah or Iran's Revolutionary Guards.

Islamic Jihad maintains its own production and storage facilities, but both rely on Iranian experts for training. Sources in Gaza say that Hamas's "military industry" is working overtime to manufacture rockets, and that the organisation can easily fire a bombardment of 80 missiles a day.

In the event of an escalation, the organisation can be expected to try to prove that it can hit more distant targets, such as Be'er Sheva almost 40 kilometres away. It is likely that nearby Ashkelon would suffer massive rockets attacks, and tens of thousands of Israeli civilians would come under indiscriminate fire.

Hamas is likely to target one kibbutz or moshav Jewish religious settlement near the border in an attempt to weaken Israeli morale. Hamas has substantial stocks of advanced Katyusha rockets smuggled in pieces through the tunnels and assembled in Gaza. It is known that these rockets are being held in reserve.

As always, the Israeli authorities are wary of sustaining large numbers of casualties, which might produce a political backlash among its relatively small population.

Israeli commanders are also bracing themselves for "asymmetric" attacks by Hizbollah's Lebanon-based Islamic militia in support of its Hamas allies and clients.

Sources say these could include assassination attempts on key figures in the Israeli government and military commands.