Israel sharpened its campaign against Gaza on Sunday, warning Palestinians in the north to flee after marines mounted a ground attack, as diplomatic efforts to halt the bloodshed intensified.
World powers prepared to meet over the spiralling bloodshed as the Palestinian death toll from the punishing Israeli air campaign hit 168 with another 1,120 people wounded, the emergency services said.
But fearing for their lives, about 17,000 people have taken shelter in installations of the UN agency for Palestinian refugees, UNRWA, said its spokesman Chris Gunness in a statement.
Despite increasing calls for a ceasefire, Israeli Prime Minister Benjamin Netanyahu said the military was hitting Hamas "with growing force," warning there was no end in sight.
"We do not know when this operation will end," he told ministers.
US Secretary of State John Kerry phoned Netanyahu to renew a US offer to help mediate a truce and he "highlighted the US concern about escalating tensions on the ground," a senior State Department official said.
Kerry also said that he was engaged with regional leaders "to help to stop the rocket fire so calm can be restored and civilian casualties prevented".
Palestinians mourn their relatives in the morgue of the Shifa hospital in Gaza City. Over a dozen Palestinians were killed in an Israeli strike on a house, hospital officials said. (AP photo)
On the Palestinian side, president Mahmud Abbas said he would ask UN chief Ban Ki-moon to "put the State of Palestine under the UN international protection system" in order to address the violence in Gaza.
As the death toll from the six-day campaign spiralled, the Gaza-based Palestinian Centre for Human Rights said most of the victims were civilians, putting their number at more than 130, among them 35 children and 26 women.
It also said Israeli had hit 147 homes and badly damaged hundreds of others.
So far, no Israelis have been killed, although militants in Gaza have pounded the south and centre of the country with about 715 rockets since the fighting began on July 8 and army spokeswoman told AFP on Sunday night. Around 160 had been intercepted, she said.
For the first time during the Israeli operation, a rocket fired from Syria hit the Israeli-occupied sector of the Golan heights but landed on empty ground, causing no casualties.
Rockets fired from Lebanon struck northern Israel on Friday and Saturday, also without causing injury.
Early Sunday, Israeli naval commandos staged a brief ground assault in northern Gaza on a mission to destroy longer-range rockets, with the army warning residents to leave the area ahead of a major assault on the sector.
Speaking on condition of anonymity, a senior Israeli military official said the area was rife with rocket launchers and would be targeted in an operation which would begin during the evening.
Hamas told Gazans to ignore the Israeli warnings.
A picture taken from the southern Israeli Gaza border shows rockets being fired from the Gaza strip into Israel. (AFP photo)
Read: Pope appeals for peace in Gaza conflict
Thousands of Gazans flee
Meanwhile in northern Gaza, even before the army's warnings went out, thousands of residents of the blockaded coastal strip were fleeing after a night of traumatic violence, an AFP correspondent reported.
"It was the middle of the night, and I gathered the children, they were so afraid," said Samari al-Atar, breaking down in tears as she described how her family fled barefoot with shooting all around.
Saturday's death toll was the highest yet with 56 people killed, including 18 people who died in a single strike on a house in Gaza City, medics said.
The blast levelled the building and sheared the facade off a neighbouring structure, exposing a kitchen and a fridge with its door ripped off.
Five people have been killed in air strikes so far on Sunday.
Neither side has shown any interest in talk of a ceasefire, with top diplomats from Britain, France, Germany and the United States due to discuss truce efforts in Vienna later on Sunday.
Pope Francis appealed to world leaders for both prayer and diplomacy to halt the bloodshed, while the German and Italian foreign ministers were both poised to head to the region to join truce efforts, their offices said.
With Palestinian civilians bearing the brunt of the violence, clashes erupted in central Paris as thousands of people protested against Israel and in support of Gazans. Demonstrators hurled projectiles onto a cordon of police who responded with tear gas.
Earlier, protesters rallied across Asia to condemn the Israeli offensive, with 3,000 gathering and hundreds more in Hong Kong, New Delhi and Jakarta. Read more
Israeli residents stand on a hill overlooking the Gaza Strip to watch the fighting between the Israeli army and Palestinian militants. (AFP photo)
No rush into land assault
Israel has warned that preparations are under way for a possible ground incursion, with Foreign Minister Avigdor Lieberman saying a decision was expected by Sunday.
But commentators said Israel was not in a rush to begin a ground operation.
"Despite the convoy of tanks heading south and the infantry brigades massing near the border with Gaza, it is obvious that Israel is in no hurry for the operation's ground phase," Amos Harel wrote in Haaretz newspaper, saying the aim was to "first exhaust diplomatic options".
The latest escalation began on June 12 when three Israeli teenagers were kidnapped and murdered, triggering a crackdown on Hamas in the West Bank and an uptick of rocket fire from Gaza, which worsened after a Palestinian teen was killed by Jewish extremists on July 2.
With multiple air raid sirens sending thousands of Tel Aviv residents fleeing for shelter, concert organisers announced Sunday the cancellation of a highly-anticipated Neil Young gig scheduled to take place in Tel Aviv on Thursday.
Israeli soldiers from the Nahal Infantry Brigade walk across a field near central Gaza Strip. (Reuters photo)