Israeli marines mounted a first ground assault on Gaza early Sunday, further escalating a deadly six-day offensive hours after the UN Security Council unanimously called for a ceasefire.
As world powers prepared to meet in Vienna over the escalating conflict, the Palestinian death toll from Israel's punishing air campaign hit 166 following the bloodiest day yet, which left 57 people dead.
So far, no Israelis have been killed, although militants in Gaza have pounded the south and centre of the country with more than 630 rockets since the fighting began on July 8, as Israel and Hamas militants faced off in the biggest confrontation since 2012.
Overnight, Israeli naval commandos raided the northern Gaza Strip on a mission to destroy longer-range rockets, dozens of which have been fired at cities as far away as Tel Aviv, Jerusalem and Hadera in the north, sending tens of thousands fleeing for cover.
"A naval commando operation took place on a beach in Gaza this morning with the aim of hitting a long-distance rocket launching site," Lieutenant Colonel Peter Lerner told reporters, saying the mission was a success, despite four soldiers being lightly injured.
Radio reports spoke of a fierce gun battle with Hamas militants in the Sudaniya district.
The ground operation came just hours after the UN Security Council unanimously urged Israel and Hamas to return to the ceasefire agreement that ended their last round of fighting in November 2012.
The chief diplomats of Britain, France, Germany and the United States were due to discuss truce efforts when they meet in Vienna later on Sunday.
Israel's air campaign claimed its highest toll on Saturday, with strikes hitting a centre for the disabled, and another that killed two nephews of Gaza's former Hamas premier, Ismail Haniya.
On Saturday night, Hamas militants fired a barrage of rockets at Tel Aviv and Jerusalem, two of which hit the occupied West Bank, causing damage to a Palestinian house in the southern city of Hebron but no casualties, witnesses told AFP.
Another six rockets were fired at metropolitan Tel Aviv shortly after dawn, setting sirens wailing across dozens of areas south of the city, including at Ben Gurion airport, army radio said.
Late on Saturday, two rockets fired from Lebanon struck northern Israel, hitting open ground near the coastal town of Nahariya.
They prompted Israeli troops to hit back with artillery fire, raising fears that the conflict in and around Gaza could spread.
It was the second time in as many days that militants in southern Lebanon had fired on Israel. Military sources suggested smaller Palestinian armed groups based in Israel's northern neighbour were responsible.
As the confrontation escalated, diplomatic efforts to secure an end to the violence gathered pace.
So far neither Israel nor Hamas has shown any interest, Egyptian mediators said on Friday.
In a sign of a likely further escalation, Israel dropped leaflets over northern Gaza, urging residents of the town of Beit Lahiya in particular to leave their homes "for their own safety".
"Civilians are requested to evacuate their residences immediately and move by 12 pm (0900 GMT) today," the leaflets said, naming locations which would prove to be most dangerous.
Israeli Prime Minister Benjamin Netanyahu has vowed that "no international pressure" will halt the campaign against Hamas militants, and army radio said Israel was looking to secure a much more comprehensive truce agreement than that which halted the fighting in 2012.
"The Israeli government at this stage is not answering ceasefire efforts because we want to know first that we have taken away Hamas's desire to do this again in another year or six months," Finance Minister Yair Lapid told public radio.
"That has not happened yet. When that happens, then we can talk."
Israel has warned that preparations are under way for a possible ground incursion, with tanks and artillery massed along the border and some 33,000 reservists mobilised out of 40,000 approved by the cabinet.
Foreign Minister Avigdor Lieberman has said he expects a political decision on a possible ground operation to be taken by Sunday.
The latest conflict kicked off on June 12 when three Israeli teenage settlers were kidnapped and murdered, triggering a major military crackdown on Hamas in the West Bank and an escalation of rocket fire from Gaza.
The brutal revenge killing of a Palestinian teenager by Jewish extremists on July 2 added further fuel to the fire, which deteriorated into all-out conflict on July 8 when Israel launched its air campaign against Gaza militants.