Israeli warplanes kept up their bombing of Gaza on Friday as Hamas rockets set sirens wailing, raising fears the conflict could spread as Washington offered help brokering a truce.
As the bloodiest battle between Israel and Hamas in 20 months escalated on its fourth day, diplomatic efforts to end the hostilities gathered pace.
US President Barack Obama phoned Israeli Prime Minister Benjamin Netanyahu to express concerns and to offer his help in resolving the crisis.
"The United States remains prepared to facilitate a cessation of hostilities, including a return to the November 2012 ceasefire agreement," the White House said, referring to a truce which ended the last major confrontation between Israel and militants from the Islamist Hamas movement in Gaza.
UN chief Ban Ki-moon and Russian President Vladimir Putin also appealed for an end to the hostilities, as the Palestinian death toll rose over 90, among them women and children.
But neither of the warring sides appeared to have any interest in backing down.
After weeks of rising rocket fire on its south, Israel lost patience and was bent on dealing a fatal blow to Hamas, with Netanyahu reportedly saying talk of a ceasefire was "not even on the agenda".
And Ismail Haniya, Gaza's former prime minister and the most senior Hamas official in the enclave, also ruled out any end to hostilities, as rockets struck deep inside Israel and sirens sent people fleeing for shelter in Jerusalem, Tel Aviv and even in the northern port city of Haifa.
"(Israel) is the one that started this aggression and it must stop, because we are (simply) defending ourselves," he said on Friday.
- Fire from Lebanon -
Hamas has called for mass demonstrations against the Israeli operation, and with Muslims marking the second Friday of the holy month of Ramadan, Israeli police were gearing up for possible disturbances.
In Jerusalem, police limited access the Al-Aqsa mosque compound to men over 50.
Israeli strikes killed more than 30 Gazans on Thursday, and another six died early on Friday, hiking the overall death toll to 98, Palestinian medics said. More than 500 people have been injured.
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So far, no-one in Israel has been killed, but a man in his 50s was in very serious condition after a Gaza rocket struck a petrol station in the southern port city of Ashdod early Friday, causing a huge explosion and major fire, medics said.
A soldier was also in "severe" condition after being wounded in a mortar attack late on Thursday, the army said.
Also on Friday, at least one rocket fired from Lebanon struck northern Israel, prompting troops to hit back with artillery fire, the army said. The rocket hit an open area near Metula at Israel's northernmost tip without causing casualties or damage.
Military officials told public radio they believed a Palestinian group had fired in solidarity with Hamas militants in Gaza, raising fears the violence in and around Gaza could spread to other fronts in a region already fraught with conflict.
- Passenger jet diverted -
As a result of the fire from Lebanon, a Polish passenger jet which was headed to Tel Aviv made an emergency stop in Cyprus, before returning to Poland, Israel's Airports Authority said.
Overnight when "a rocket was fired from Lebanon, a flight of the Polish Lot carrier on its way to Israel was instructed to wait in the air. The pilot decided to head to an alternative airport in Larnaca, and after waiting there, returned with the passengers to Poland."
During the night, the Israeli army hit 50 targets, and it also bombed 21 Hamas-owned structures in the past 24 hours, spokesman Lieutenant Colonel Peter Lerner said.
One of the strikes hit the port in Gaza City, setting boats alight, including Gaza's Ark, a Palestinian-built protest vessel which was preparing to run Israel's naval blockade, an AFP correspondent said.
Since the start of the operation, 410 rockets fired by militants in Gaza have struck Israel, while another 120 have been intercepted by the Iron Dome anti-missile system.
Another three were shot down Friday over the Tel Aviv area, the army said, with Hamas's armed wing claiming it had fired "four M75 missiles at Ben Gurion airport" just outside the city.
Israel has confirmed preparations are under way for a possible ground attack, with tanks and artillery massed along the border and some 33,000 reserves mobilised out of the 40,000 approved by the cabinet.
"We are still facing a difficult, complex and complicated campaign," Netanyahu warned after an hours-long meeting with his security cabinet on Thursday.