PROPOSAL REVISED
Egypt said on Tuesday it was revising an unconditional ceasefire proposal that Israel had originally accepted but Hamas rejected, and that a new offer would be presented to Palestinian representatives.
Egyptian officials said an Israeli delegation had held brief talks in Cairo on Wednesday, but gave no further details.
In previous bouts of fighting between Israel and its neighbours, the United States has often leaned on the Israelis to stop after incidents that caused high civilian casualties. Washington appears to have less sway with either side this time.
Israel says Hamas is ultimately responsible for such casualties because its fighters, including rocket-launching squads, operate in densely populated residential areas. The army has warned civilians to evacuate whole neighbourhoods before military operations.
The United Nations said Israeli bombing over the past three weeks has destroyed or severely damaged 4,000 Palestinian homes, scores of schools and almost two dozen health facilities.
Some 240,000 people in the Gaza Strip had sought refuge in UN schools or with relatives or friends, the UN said.
Palestinian president Mahmoud Abbas said on Wednesday Gaza has become a "humanitarian disaster area" and urged the UN and international aid agencies to assume responsibility for meeting the needs of the Palestinians in the battered enclave.
"I call for the use of all tools available within the United Nations to provide relief and help to the Palestinian people during this grave humanitarian crisis," Abbas said in a letter to Ban, according to official Palestinian news agency Wafa.
Both US President Barack Obama and the UN Security Council have called for an immediate ceasefire to allow relief to reach Gaza's 1.8 million Palestinians, followed by negotiations on a more durable end to hostilities.
Amidst the bloodshed, Switzerland said on Wednesday it was taking soundings about the possibility of holding a Middle East peace conference later this year following a request from Abbas.
The Swiss Foreign Ministry said that as custodian of the 1949 Geneva Conventions laying down the rules of war, "Switzerland transmitted this request to the states parties and is currently carrying out informal consultations", but it noted a broad consensus would be needed on the terms of reference and the expected results.