UN chief Ban Ki-moon and US Secretary of State John Kerry were in Cairo Tuesday in a bid to broker a truce between Israel and Hamas after two weeks of fighting which has left over 570 Palestinians dead.
Many of those killed in the relentless Israeli campaign of shelling and airstrikes in the Gaza Strip, in its 15th day, were women and children. On the Israeli side 27 soldiers and two civilians have died.
World powers have urged Hamas to accept an Egyptian-brokered ceasefire and stop raining rockets into Israel from the Gaza Strip, demands it has so far resisted.
"Only Hamas now needs to make the decision to spare innocent civilians from this violence," Kerry said, and UN chief Ban Ki-moon appealed for the violence to "stop now".
Kerry, who arrived in Cairo to try and intensify truce efforts, pledged $47 million in humanitarian aid for the battered Gaza Strip.
Arab League chief Nabil al-Arabi too urged Hamas to accept an Egyptian proposal to end the fighting it had turned down last week.
Kerry plans to hold his meetings Tuesday with the Egyptian leadership including President Abdel Fattah al-Sisi.
However US officials acknowledge that the truce efforts could prove trickier than in the past as Egypt -- long the key regional broker -- had little leverage with Hamas after the army overthrew Islamist president Mohamed Morsi last year.
The top US diplomat defended ally Israel's right to strike against Hamas militants, but voiced concern over the massive civilian violence.
"We are deeply concerned about the consequences of Israel's appropriate and legitimate effort to defend itself," he told reporters as he met with the UN chief, urging Hamas to accept the Egyptian-proposed ceasefire.
Ban said Hamas "should immediately stop firing rockets," adding that while he understood Israel's military response, "there is a proportionality and ... most of the death toll (has been) Palestinian people."
- 100,000 displaced -
Fresh Israeli strikes and Gaza emergency services spokesman Ashraf al-Qudra said 16 Palestinians were killed on Tuesday, raising the death toll since Israel launched its operation on July 8 to 576.
Israel says its campaign aims to stamp out rocket fire from Gaza, and the ground phase of the operation to destroy tunnels burrowed into Israel by Hamas, the main power in the coastal strip.
Since the offensive began huge numbers of Gazans have fled their homes, with the UN saying more than 100,000 people have sought shelter in 69 schools run by its Palestinian refugee agency (UNRWA).
On Tuesday morning, the Israeli army announced two of its soldiers had been killed in clashes in Gaza.
That brought its toll to 27 soldiers killed since the start of the operation, including 13 on Sunday, the bloodiest single day for the Israeli military since the Lebanon war of 2006.
Two Israeli civilians, both hit by rocket fire, have been killed.
- Hamas digs in -
Hamas on Monday reiterated its insistence on a lifting of Israel's blockade of Gaza and the release of prisoners to halt its rocket fire.
"The conditions for a ceasefire are... a full lifting of the blockade and then the release of those recently detained in the West Bank," its leader in Gaza, Ismail Haniya, said on television.
"We cannot go backwards, to a slow death," he said, referring to the Israeli blockade in force since 2006.
"The conditions of the Palestinian resistance constitute the minimum required for a truce. The resistance and the sons of our people who have made such sacrifices in this mad war cannot accept anything less."
Meanwhile, Hamas leader Khaled Meshaal and Palestinian president Mahmud Abbas held talks in Doha, pledging to work together for a ceasefire and to lift the blockade on Gaza.
But there has been no let-up since the operation began with 116 rockets hitting Israel on Monday, one striking the greater Tel Aviv area, and another 17 shot down, the army said.
Violence also broke out in the West Bank, where an Israeli shot dead a Palestinian who had been throwing stones at his car, Palestinian security sources said.
An Israeli army spokeswoman said the military was investigating the death, which she said took place during "a violent riot".
Israeli police said Palestinians had also rioted in east Jerusalem neighbourhoods Monday night, with no casualties.
Elsewhere in the West Bank, an Israeli was seriously wounded after a Palestinian opened fire at him from a travelling car, the army said.