Two Palestinians have been wounded, one seriously, in an Israeli missile strike in the northern Gaza Strip town of Beit Lahiya.
One of the men, a 29-year-old member of the Palestinian security forces, was critically wounded in the attack.
Meanwhile, Israel has said it will not be held to 'ransom' after Palestinian militants, believed to be holding a captured Israeli soldier, said their demands for prisoner releases must be met before 4am tomorrow morning (Irish time).
A statement by Hamas's military wing and two other groups said Israel would otherwise have to face unspecified consequences.
The office of the Israeli Prime Minister, Ehud Olmert, rejected the demand.
Earlier, Israeli tanks and bulldozers moved inside northern Gaza, as the operation continues to rescue Corporal Gilad Shalit, 19, who was captured last weekend in a cross-border raid from the Gaza Strip by three Palestinian factions, including the armed wing of Hamas.
The Israelis attacked a school building, a university campus and Gaza's only power plant.
Israeli military sources have said, however, that the operation is not part of an incursion against Palestinian militants. They describe it as a pinpoint operation to locate tunnels and explosives near the border fence.
The United Nations has described the recent attacks as a breach of international humanitarian law.
The UN special envoy to the Middle East, Alvaro de Soto, has criticised both sides for their part in recent fighting.
The Palestinian President, Mahmoud Abbas, has called on the international community to intervene in the conflict.
