Israeli tanks, planes and ground forces pounded Gaza on Monday and the defense minister said the offensive against Hamas militants in the Palestinian enclave would go on until Israel was safe.
International efforts to secure a ceasefire moved ahead with French President Nicolas Sarkozy and Middle East special envoy Tony Blair visiting the region, but they seemed able to offer little beyond words.
The death toll in besieged Gaza rose on Monday to at least 530 people. Victims included three Palestinian children and their mother when a tank shell hit their home in Gaza City and seven members of another family were killed in a refugee camp.
The Israeli army said "many dozens" of Islamist fighters had been killed since ground troops went in on Saturday in a stated attempt to end rocket fire by Hamas into southern Israel.
"Hamas has so far sustained a very heavy blow from us, but we have yet to achieve our objective and therefore the operation continues," Israeli Defense Minister Ehud Barak said.
A Hamas official said a delegation from the Islamist group would head for talks in Egypt, which has also opened contacts to achieve a ceasefire. But senior Hamas political leader Mahmoud Zahar urged Hamas forces to fight on "in the name of God."
"They legalized for us knocking down their synagogues when they hit our mosques, they legalized for us knocking down their schools when they hit our schools," he said in a speech broadcast in Gaza.
Gunbattles intensified in eastern Gaza City and in the north of the strip on Monday. Militants fired mortars and grenades and detonated mines, and claimed to have hit a troop carrier.
They were also trying to lure Israeli soldiers into built-up areas, witnesses said.
A military spokeswoman said the air force bombed more than 30 targets, including homes of Hamas members used as weapons depots, tunnels and a suspected anti-aircraft rocket launcher.
Four Israelis have been killed by salvoes fired into Israel since the offensive began. An Israeli soldier was killed in fighting on Sunday and 48 have been wounded since the invasion.
Israel’s advances into Gaza have carved the 40-km long coastal territory, home to 1.5 million people, into two zones and forces have surrounded its largest urban area, Gaza City
Bombs on Monday hit a hospital morgue where a family were mourning a paramedic killed in an airstrike on Sunday. Three people were killed and 17 wounded, medical workers said.
Gaza residents were in dire need of food, medical supplies and other aid but the hostilities were hampering relief efforts, aid agencies said.
At a house at the Beach refugee camp, Umm Ala Mrad sat on a mattress surrounded by her nine children. An Israeli warship intermittently fired shells, hitting buildings by the shore.
"Every time a shell is fired from the sea I rush to carry my children out of the house. But how and what should I do, who should I carry first and who should I leave for a next go," she asked a reporter.
Czech Foreign Minister Karel Schwarzenberg, heading an EU peace mission, could offer her little comfort. "We do not have a specific plan for a ceasefire because the ceasefire as such must be concluded by the involved parties," he said in Jerusalem.
"We can mediate, we can assist a solution but it’s not up to us to propose the conditions."