Israel ordered ground forces to the Gaza border yesterday and threatened a "crushing" response after Israeli towns were hit by the first major Hamas rocket barrage from the coastal territory since Israel's pullout two weeks earlier.
In an attempt to strengthen its deterrence, Israel also resumed air strikes against Hamas targets, killing at least four Hamas militants, hitting several alleged weapons workshops, and imposed a blanket closure that bars all Palestinians from its territory.
Prime Minister Ariel Sharon called his Security Cabinet for a meeting later yesterday to approve the military's response, expected to last for several days, though a large-scale ground operation appears unlikely.
The timing of the Cabinet meeting suggested a sense of urgency.
The Cabinet session comes as Sharon faces a major leadership challenge in his Likud Party this week over the Gaza pullout. Sharon's challenger, former Prime Minister Benjamin Netanyahu, has warned the withdrawal will endanger Israel.
The barrage of 39 rockets, with five Israelis hurt, could give him a boost in the battle against Sharon.
The escalation was set off by an explosion Friday at a Hamas rally in the crowded Jebaliya refugee camp in which at least 15 Palestinians were killed. Witnesses said the blast went off near a pickup truck carrying Hamas militants and homemade rockets.
Hamas blamed Israel for the blast and said it fired rockets on Israeli border towns in retaliation. However, the Palestinian Authority held the Islamic militants responsible, saying that they apparently mishandled explosives.