The 16-day conflict has claimed the lives of 718 Palestinians, most of them civilians, Palestinian health officials say. Israel has lost 32 soldiers, all since July 17, when it widened its air campaign into a full-scale ground operation aimed at halting rocket fire from Gaza and destroying a sophisticated network of cross-border tunnels.
Two Israeli civilians and a Thai worker in Israel have also been killed.
Appearing with visiting British Foreign Secretary Philip Hammond, Israeli Prime Minister Benjamin Netanyahu made no reference to the cease-fire efforts in underscoring his determination to neutralize the rocket and tunnel threats.
More than 2,000 rockets have been fired at Israel from Gaza since July 8, and the Israeli military says it has uncovered more than 30 tunnels leading from Gaza to Israel, some of which have been used by Hamas to carry out attacks.
"We started this operation to return peace and quiet to Israel," Netanyahu said in Jerusalem. "And we shall return it."
Six members of the same family and an 18-month-old infant boy were killed when an Israeli airstrike hit the Jebaliya refugee camp in the early morning hours, according to Gaza police and health officials. Twenty others were injured in the strike, they said, and rescuers were digging through the rubble of flattened homes, looking for survivors.
Heavy fighting was reported along the border of central Gaza, according to Gaza police spokesman Ayman Batniji. Israeli troops fired tank shells that reached parts of the Bureij and Maghazi refugee camps. There were no immediate reports of injuries.
Clashes also erupted between Palestinian fighters and Israeli troops in the northern town of Beit Lahiya, and the sound of explosions was audible across the town, Batniji said.
Israeli naval vessels meanwhile fired more than 100 shells along the coast of Gaza City and northern Gaza, the spokesman said. Rescue teams were prevented from operating in the area because of the heavy fire, he added.
U.S. Secretary of State John Kerry flew to Israel Wednesday on an Air Force jet, despite a ban imposed a day earlier by the U.S. Federal Aviation Administration on commercial flights into Ben-Gurion International Airport because of Hamas rocket fire.
The FAA dropped the ban just before midnight, but European airlines have extended their cancellations through Thursday.
"We certainly have made steps forward," Kerry said in Jerusalem Wednesday, without elaborating. "There's still work to be done."
Underscoring the challenges he faces, the leader of Hamas insisted the Islamic militants would not relent until their main demand of lifting an Egyptian-Israeli blockade of the Gaza Strip is met.
"When it comes to the balance of power in this crisis between us and Israel, they are the executioners, the aggressors, the occupiers, the settlers, and we are the true owners of the land," Khaled Mashaal said in a televised speech from his home-in-exile in Doha, Qatar. "We will not accept anything but the end of the siege."
Israel imposed the blockade in 2006 after Hamas and other militants abducted an Israeli soldier in a deadly cross-border raid. It tightened the siege in 2007 after Hamas seized power from forces loyal to Western-backed Palestinian President Mahmoud Abbas, but had eased some of the restrictions in recent years.
Egypt tightened its own restrictions last year after the overthrow of a Hamas-friendly government in Cairo and has destroyed many of the cross-border smuggling tunnels that sustained Gaza's economy, and which were also used by Hamas to bring in arms.
Enav reported from Jerusalem
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