World efforts to broker a ceasefire in war-torn Gaza gathered pace Monday as Israel pressed a blistering 14-day assault on the enclave, pushing the Palestinian death toll to 548.
As Washington and the United Nations demanded an "immediate ceasefire" in the battered Palestinian enclave, there was no let up in the Israeli offensive with another 31 Gazans killed in a series of strikes.
And Israel said troops killed 10 Hamas militants after they sneaked over the border through a network of tunnels that the army has been trying to destroy in an intensive four-day ground operation.
With growing concern over the number of civilian deaths, UN chief Ban Ki-moon arrived in Cairo for top-level talks on ending the hostilities, with US Secretary of State John Kerry also expected to fly in later Monday.
Following the deadliest day in Gaza since 2009, when at least 140 Palestinians were killed on Sunday, medics pulled another 68 bodies from the rubble early Monday, emergency services spokesman Ashraf al-Qudra said.
And 31 others were killed in a series of fresh strikes across the Gaza Strip.
In the latest bloodshed, tank-shelling on a hospital in Deir al-Balah in central Gaza killed four people, and a family of nine was killed in the southern city of Rafah, seven of them children, Qudra said.
As the diplomatic efforts gathered steam, hundreds of people could be seen flooding out of the northern town of Beit Hanun, a day after many thousands fled an intensive Israeli bombardment of the eastern Gaza City district of Shejaiya.
On Sunday, at least 72 people were killed in Shejaiya during a punishing Israeli operation which reduced much of the district to rubble and left charred bodies lying in the streets.
And an Israeli tank shell killed three more in the district on Monday.
- Militants infiltrate Israel -
Since the Israeli operation began on July 8, huge numbers of Gazans have fled their homes, with more than 85,000 people taking shelter in 67 schools run by UNRWA, the UN agency for Palestinian refugees, a spokesman said.
By Monday morning, a UN school on the outskirts of Shejaiya was packed to overflowing with people seeking shelter, many sleeping in the corridors, an AFP correspondent said.
And in Gaza City's Shifa hospital, several families could be seen sleeping in gardens in the hope they would be safe from the bombing.
Meanwhile, in southern Israel, the military said troops had killed "more than 10" Hamas militants who managed to cross the border through tunnels. It said there were "two terrorist squads," one of which was hit by an air strike
Military radio said the second squad engaged in a fierce gunbattle with troops in which several soldiers were wounded, without giving further details.
On Sunday, 13 Israeli soldiers were killed inside Gaza, raising to 18 the total number of soldiers killed since a ground operation began late on Thursday.
That represented the army's heaviest loss in eight years and left the Jewish state in mourning.
The attack was claimed by Hamas militants from its armed win, the Ezzedine al-Qassam Brigades, which said it had carried out "an operation behind enemy lines in response to the massacre in Shejaiya".
Late on Sunday, the Qassam Brigades claimed it had captured an Israeli soldier in a report that the army said it was checking, but which Israel's UN ambassador said was untrue.
Meanwhile, Hamas leader Khaled Meshaal and Palestinian president Mahmud Abbas held talks in Doha, pledging in their first meeting since the launch of Israel's assault to work together for a ceasefire and to lift the blockade, officials said.
- Hezbollah hails Hamas -
In Lebanon, Hezbollah chief Hassan Nasrallah offered his full backing to "Hamas's strategy" in a telephone conversation with Meshaal, describing its conditions for ending the violence as "just".
Hamas has so far rejected truce calls, insisting Israel meet a series of conditions before halting its fire -- including an end to the eight-year blockade on Gaza and the release of scores of prisoners from Israeli jails.
Despite rising concern over the number of civilian casualties, Prime Minister Benjamin Netanyahu has accused Hamas for using innocent civilians "as human shields" and insisted the military operation had "very strong support" from the international community.
Although Israel said Sunday it was expanding its ground operation to destroy cross-border tunnels, Defence Minister Moshe Yaalon suggested the mission could be accomplished within days.
There was no let-up in rocket and mortar fire by Gaza militants on Monday with 40 hitting Israel, one striking the greater Tel Aviv area, and another 11 shot down, the army said.