Israeli troops raided two Gaza refugee camps early today, sparking gunbattles that killed 14 Palestinians - including an eight-year-old boy.
It came a day after militant groups choreographed an elaborate attack on soldiers at the main Gaza crossing into Israel.
In the raid, at least 81 Palestinians, among them nine left in a critical condition, were wounded in the ongoing fighting, said Abdullah Abu Samahadana, governor of central Gaza. Eight of the dead were militants.
The army said it had raided the Bureij refugee camp in a "pinpointed operation against the terrorist infrastructure ... focusing on terrorist cells who frequently fire mortar shells and activate explosive devices against Israeli civilian and military targets."
In intense fighting, Palestinians fired anti-tanks missiles and detonated explosives at forces, the army said. The army confirmed hitting at least one armed Palestinian.
Fighting has intensified in the Gaza Strip in recent weeks - with the army carrying out targeted killings and raids on Palestinian towns while Palestinian militants staged attacks - as each side tries to make a planned Israeli withdrawal from the Gaza Strip look like a victory.
Palestinian Cabinet minister Mr Saeb Erekat condemned today's raid, calling for a return to negotiations on the US-backed "road map" peace plan.
"At a time when they're speaking about withdrawing from Gaza, they're destroying Gaza," Mr Erekat said.
Yesterday, three main Palestinian militant groups staged an elaborate attack at the Erez Crossing, sending a suicide bomber and militants with assault rifles in vehicles disguised as Israeli army jeeps to attack soldiers guarding the heavily fortified area. The carefully co-ordinated attack began when a taxi
laden with explosives blew up near a military checkpoint.
Four Palestinian assailants and two Palestinian policemen were killed in the attack. No Israelis were hurt.
Before dawn today, Israeli forces, with at least two Apache helicopter gunships hovering overhead, moved slowly down alleys and side streets on the outskirts of the Bureij and Nusseirat refugee camps. Sniper units were stationed on rooftops, witnesses said.
Calls for gunmen to come out and fight the Israelis came over mosque loudspeakers in Bureij and dozens of men from several militant factions poured into the streets. Sounds of intensive gunfire punctuated the air.
Area residents gathered in the emergency room of Al Aqsa Martyrs' Brigades Hospital in nearby Deir el-Balah, offering assistance to the harried medical staff.
In Nusseirat, soldiers surrounded the homes of two leaders of the Popular Resistance Committees, an umbrella group of members of several militant factions. By midmorning, the army had redeployed in farms around the refugee camp.
Among the dead were boys aged eight, 12, and 15.