DEBKAfile's military sources report that Hamas does not propose to put its entire 15,000-strong army in harm's way against the expected Israeli military invasion. It will confine its resistance to small pockets and sabotage and let Israel troops occupy most of Gaza Strip territory. Assuming the incoming force will stop short of conquering Gaza City and put it to siege, Hamas planners believe this siege force will be Israel's Achilles heel. They propose to wear it down over weeks by nocturnal guerrilla forays from within Gaza City and force an inconclusive end to the conflict.

Thousands of Hamas combatants have begun infiltrating Gaza City after shedding their uniforms and are taking over civilian apartments.

DEBKAfile's military sources disclose that Israel's war planners have factored Hamas' thinking into their calculations and built tactics to catch them unawares.

Hamas strategists expect the Israeli ground operation to start with a simultaneous three-prong incursion of armor and special forces from the north, the east and the south. The invaders will occupy most of the 20x40-kilometer area of the Gaza Strip within 5 to 7 days at most, skirting and encircling Gaza City and other main towns. They will then, according to Hamas' calculations, carve the territory up into five pockets, each with its own military commander.

Pocket 1 will extend from the southernmost Philadelphi belt on the Egyptian border up to the southern outskirts of Khan Younis. Israeli units will then set about destroying the network of hundreds of smuggling tunnels which has kept Hamas supplied with arms, fuel and reinforcements through Sinai. Cairo may have tacitly approved the Israel plan.

Pocket 2 will cover the Khan Younes district up to the Kissufim junction.

Pocket 3 will cover the central region of the Gaza Strip up to the Karni Crossing, including the Moazi and El Bureij refugee camps.

Pocket 4 will encompass Jebalya, Beit Hanoun, Beit Lahiya, the primary rocket and missile sites, up to the northern border with Israel.

Pocket 5 An Israeli force will encircle Gaza City and send detachments into the town to liquidate Hamas targets and operatives from allied Palestinian terror groups.

Hamas believes the IDF force will be at its most vulnerable when its Gaza City siege force is faced with an active fighting front of 3,000-5,000 armed Palestinians. By day, they will mingle with the civilian population and by night emerge from hideouts in private homes to hit the Israeli armored forces from the rear with anti-tank weapons and suicide bombers.

The Palestinian group's leaders are counting on inflicting casualties that will mount up week after week and wear Israeli forces down until they are driven into an ignominious retreat.