At least nine Palestinians have been killed during a second day of clashes with Israeli forces in the Gaza Strip.
Stone-throwing youths confronted Israeli tanks
Four Palestinians died on Tuesday, when Israeli troops and tanks moved into the northern town of Beit Lahia.
Israel says it is trying to destroy launch sites for home-made rockets that have been fired at Israeli targets.
As the unrest continued, Prime Minister Ariel Sharon insisted that Israel would continue to target militant Palestinian leaders for assassination.
Clashes in Gaza have surged since Mr Sharon announced unilateral plans to withdraw Israeli settlements from the coastal territory in February.
A column of tanks backed by helicopter gunships entered Beit Lahia early on Wednesday, as soldiers searched houses looking for militants involved in firing Qassam rockets.
At least 15 rockets have landed over the border in recent days, injuring five Israeli civilians.
The BBC's Peter Greste, in the northern Gaza Strip, says Palestinian youths fought the tanks and armoured vehicles with whatever came to hand; stones, home-made grenades and smuggled Kalashnikovs.
Our correspondent saw angry young teenagers run to within a few metres of the tanks to toss whatever they had in their hands.
Ambulances ran a constant shuttle for the dead and wounded, some as young as 14, our correspondent said.
About 40 Palestinians were wounded during the incursions.
An Israeli army spokesman said: "Everyone we hit was either armed or
The recent killings of Hamas leaders Sheikh Ahmed Yassin and Abdel Aziz al-Rantissi have led to increased tensions in Gaza.
On Wednesday, Mr Sharon promised Israel would "not let up" on the perpetrators of "terror".
"In that way we got rid of the first murderer, and in that way a few days ago we got rid of the second murderer, and that is not the end," he said in a speech at the port city of Ashdod - the site of a 14 March suicide bombing .
Mr Sharon's message was met with defiance from Hamas.
"These threats will not frighten us," Hamas activist Mahmoud al-Zahar told about 10,000 people attending a memorial for Rantissi in Gaza.
"The programme of resistance will continue. We are sending clear messages to Sharon: You will be defeated and removed through this land through resistance."
Sheikh Yassin was killed on 22 March as he returned from a mosque.
His successor, Mr Rantissi, died on Saturday. Both were killed by Israeli missiles.