The Department of Foreign Affairs and Trade said the embassy in Tel Aviv would arrange a one-off “assisted departure” for Australian citizens in Gaza early on Sunday. They would be taken by road to Amman in Jordan.

An Israeli naval commando unit raided a Palestinian compound early on Sunday,  which it said had been used as a launching site for long-range rockets. Four Israeli soldiers were lightly wounded.  It was the first known raid inside Gaza since military operations began six days ago.

More than 100 rockets struck Israel the day before, the Israeli Defence Force said, and sirens rang out in Jerusalem and Tel Aviv.

Palestinian authorities said 50 people were killed in air strikes on Saturday, the bloodiest day of fighting since Tuesday, which pushed total casualties to 156. The Israeli military was dropping leaflets into Gaza’s north on Sunday warning residents to evacuate before further strikes.

The federal government said it was aware of 20 Australians  in the territory. “The retaliatory acts from both sides that have led to civilian deaths and injuries are deeply regrettable,” Foreign Affairs Minister Julie Bishop said.

‘‘Australians in Gaza are urged to leave as soon as possible,’’ Ms Bishop told Sky News on Sunday. ‘‘We know there are about 20 or so Australians registered who are in Gaza and I believe we have assisted 17 so far.’’

Ms Bishop warned that if Australians delayed contacting the embassy, they risked having to find their own way out of Gaza.

Australians were warned to avoid the Gaza Strip entirely and reconsider the need to travel to Israeli cities within 40 kilometres of its border, such as Beersheba.

Ms Bishop said she was concerned about the unpredictable situation amid the “possibility of further Israeli military operations against militants”.

The conflict showed no signs of abating despite international calls for a ceasefire the day after Israeli Prime Minister Benjamin Netanyahu vowed to continue military operations until “quiet is restored”.

Israel launched artillery fire across its northern border with Lebanon after three rockets were fired from the country’s south into the Israeli city of Nahariya.

The UN Security Council called for an urgent ‘‘de-escalation of the situation, restoration of calm, and reinstitution of the November 2012 ceasefire’’. It urged both sides to renew direct talks.

The Israeli newspaper Haaretz reported that 21 people were killed in a single air strike on the home of Gaza’s police chief on Saturday night, the deadliest since operations began on Tuesday.

A situation report released on Friday by the UN Office for the Co-ordination of Humanitarian Affairs estimated that 70 per cent of all people killed have been civilians.

The Israeli government has accused Hamas of packing its missile launching stations with civilians in an attempt to discourage retaliation.