Israel has killed 30 Palestinians and injured more than 90 others in air attacks on the Gaza Strip since Tuesday, the Palestinian health ministry has said.
The victims include six children and three women as well as the head of the Palestinian Islamic Jihad (PIJ) rocket force and his deputy.
Palestinian factions in Gaza continued to fire rockets in retaliation from the besieged coastal enclave into Israel, killing one person on Thursday.
Amid mediation efforts by Egypt, neither side seemed ready to douse the worst flare-up since August, now in its third day.
“We are at the height of a campaign, both offensive and defensive,” Israeli Prime Minister Benjamin Netanyahu said in a videotaped statement issued during a visit to an air base.
“Whoever comes to harm us – his blood is forfeit.”
The deaths of Ali Ghali and Ahmed Abu Daqqa brought to five the number of senior figures from PIJ killed since Israel began attacking Gaza early on Tuesday.
Egypt said it was trying to secure a truce but so far, its efforts have proved futile.
Cairo, which hosted senior PIJ official Mohammad al-Hindi for talks, was circumspect about prospects for a ceasefire.
“Egypt’s efforts to calm things down and resume the political process have not yet borne fruit,” Egyptian Foreign Minister Sameh Shoukry told reporters.
Meeting Jordanian, French and German counterparts in Berlin, Shoukry urged “peace-sponsoring countries to intervene and stop the attacks” and said Israel must “stop the unilateral measures that aim to destroy the future of the Palestinian state”.
Among terms for a truce, PIJ wants an end to Israeli assassinations of its leaders.
“Islamic Jihad is demanding that if there is to be a ceasefire, Israel must commit to not assassinate any more of their leaders. This is something Israel says it’s not going to do. We’ve seen five of their leaders over the course of the past two days assassinated by Israel and they’re saying they have the right to do that,” said Al Jazeera correspondent Mohammed Jamjoom.
Israel appears to be hoping the PIJ, depleted of rockets and commanders, would halt hostilities unilaterally.
The initial Israeli air attacks on Tuesday that set off the exchange of fire killed three senior PIJ fighters and at least 10 civilians, most of them women and children.
More than 90 people have been wounded in the attacks that destroyed five buildings and damaged more than 300 apartments, said Salama Marouf, chairman of the media office for the Hamas group that governs Gaza.
Israel has kept crossings for the movement of people and goods closed since Tuesday, blocking travel entirely, even for urgent humanitarian needs, and preventing patients from accessing medical treatment not available in Gaza, human rights groups have said.
Some “292 patients and companions were prevented from accessing medical treatment that is unavailable in Gaza, many of them cancer patients and others in need of life-saving treatment provided by hospitals in the West Bank or Israel”, the Israeli rights group, Gisha – Legal Center for Freedom of Movement, said in a statement.
“The closing of Beit Hanoon Crossing puts additional lives at risk by preventing urgent evacuations, which may be needed, of civilians injured during the assault.”
Gisha, along with rights organisations Adalah, Physicians for Human Rights – Israel and Al Mezan, sent an urgent letter to several Israeli officials demanding that Israel stop all harm to civilians and enable humanitarian access, immediately.
“Security challenges, including risks posed during active hostilities, do not exempt Israel from its humanitarian obligations to residents of Gaza,” the organisations said, concluding that “the violation of these principles raises serious concern of flagrant violations of the rules of war that may amount to war crimes.”