The world's top diplomats are trying to end the week-long convulsion of Israeli-Palestinian violence.
President Barack Obama sent his secretary of state to the region on an emergency mission and the UN chief appealed from Cairo for an immediate cease-fire.
Israel and Gaza's militant Hamas rulers have staked tough, hard-to-bridge positions, and the gaps keep alive the threat of an Israeli ground invasion.
Grieving Gazans were again burying militants and civilians killed in ongoing Israeli airstrikes, and barrages of rockets from Gaza sent terrified Israelis scurrying to take cover.
From Egypt, UN chief Ban Ki-moon said : "This must stop, immediate steps are needed to avoid further escalation, including a ground operation. Both sides must hold fire immediately ... Further escalation of the situation could put the entire region at risk."
US Secretary of State Hillary Clinton is heading to the Middle East from Cambodia, where she had accompanied Mr Obama on a visit. She will meet Israeli Prime Minister Benjamin Netanyahu in Jerusalem, Palestinian President Mahmoud Abbas in the West Bank and Egyptian leaders in Cairo.
The US considers Hamas, which has killed hundreds of Israelis in suicide and other attacks, to be a terror group and does not meet its officials. The Obama administration blames Hamas for the latest eruption of violence and says Israel has the right to defend itself. At the same time, it has warned against a ground invasion, saying it could send casualties spiralling.
Civilians account for 54 of the 113 Palestinians killed since Israel began an air onslaught that has so far included nearly 1,500 strikes. Some 840 people have been wounded, including 225 children, Gaza health officials said.
Three Israeli civilians have also been killed and dozens wounded since the fighting began, the numbers possibly kept down by a rocket-defence system that Israel developed with US funding. More than 1,000 rockets have been fired at Israel this week, the military said.
Israeli Prime Minister Benjamin Netanyahu said he was exploring a diplomatic solution, but would not balk at a broader military operation.