Israeli air strikes pounded Gaza Sunday, killing at least 16 people, after Prime Minister Benjamin Netanyahu warned the bloody offensive would continue as long as necessary.

Israel and Hamas, who have been fighting for 48 days, looked unlikely to end their deadly face-off even after Egypt called for an indefinite ceasefire and new truce talks to end a war that has killed more than 2,100 Palestinians and 68 Israelis, mostly soldiers.

One of Sunday's air strikes killed Hamas financial official Mohammed al-Ghul as he was travelling by car in Gaza City, Israel's army said in a statement. Gaza medics confirmed the death.

A later strike on northern Gaza killed a mother and four children from the same family, medics said, as the day's death toll reached at least 16, including six children.

Israel's offensive began with the stated aim of stamping out rocket attacks from Gaza and was later expanded to include the destruction of Hamas tunnels used for cross-border attacks inside Israel.

"Operation Protective Edge will continue until its aims are achieved... it may take time," Netanyahu said of the offensive launched on July 8.

Israel on Sunday carried out 27 strikes while more than 120 rockets were fired from Gaza, including one intercepted on Sunday evening over Jerusalem, the army said. One rocket caused damage to a house but no one was injured, it added.

The Israeli ambulance service said that three people were wounded by Palestinian fire at the Erez crossing point between Israel and Gaza, at least one of them seriously.

Police identified the injured as Arab public transport drivers waiting in the crossing's car park.

- PM warns Lebanon, Syria -

At a special cabinet session at the defence ministry in Tel Aviv, Netanyahu repeated his warning of harsh retribution for the death of a four-year-old Israeli child on Friday in a rocket strike on a kibbutz near the Gaza border.

"Hamas is paying, and will continue to pay, a heavy price for the crimes it carries out," he said.

"I call on residents of Gaza to immediately leave any structure from which Hamas carries out terror activity against us. All such sites are a target for us."

Hamas dismissed Netanyahu's warnings to civilians as a sign of weakness.

"The occupation (Israel) has failed in confronting the resistance (Hamas) in the field, and has resorted to threats of assassination and other threats designed to scare us. But the will of our people will not be broken," spokesman Sami Abu Zuhri said in a statement.

Netanyahu also added a veiled warning to neighbouring Lebanon and Syria after overnight rocket fire into Israel.

Earlier on Sunday, five rockets fired from Syrian-controlled territory slammed into the Israeli-occupied sector of the Golan Heights but caused no casualties, the Israeli army said.

Late Saturday, a rocket fired from Lebanon struck northern Israel, causing damage but no casualties.

Israel has so far not responded to either attack.

- Egypt truce talks bid -

In a statement on Saturday, the Egyptian foreign ministry urged "concerned parties" in the Gaza conflict to accept an open-ended truce and resume indirect negotiations in Cairo.

But there was still no sign of either side adopting the ceasefire.

Since a previous round of frantic Egyptian diplomacy collapsed on Tuesday, shattering nine days of calm, around 100 Palestinians and the Israeli boy have been killed in the violence.

Previous ceasefires with fixed timeframes have failed to give Egyptian mediators shuttling between Israeli and Palestinian negotiating teams enough time to broker a deal acceptable to both.

Hamas, Gaza's Islamist de facto ruler, says any truce must provide for a lifting of Israel's crippling eight-year blockade of the territory and the opening of a seaport and airport.

The invitation to new truce talks came after a meeting on Saturday between Egyptian leader Abdel Fattah al-Sisi and Palestinian president Mahmud Abbas.

"What interests us now is putting a stop to the bloodshed," Abbas said.

"As soon as a ceasefire goes into effect, the two sides can sit down and discuss their demands," he said, adding that, as in previous rounds of talks, Hamas would be represented in the Palestinian delegation.

Hamas spokesman Sami Abu Zuhri told AFP that "any proposal offered to the movement will be discussed".

At least than 2,120 Palestinians and 68 people on the Israeli side, all but four of them soldiers, have been killed since July 8.

The United Nations says 70 percent of the Palestinian victims were civilians, and that among the dead were 478 children.

Around 460,000 people have fled their homes in Gaza -- more than a quarter of the densely-populated Mediterranean enclave's 1.8 million population.

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