President Joe Biden told Prime Minister Benjamin Netanyahu Thursday that US policy on Israel depends on the protection of civilians in Gaza, in his strongest hint yet of possible conditions to Washington's military aid.
The warning from the White House came after Israel's killing of seven aid workers unloading food in famine-threatened Gaza on Monday sparked international outrage and calls for Israel to rein in its offensive, now nearing its seventh month.
In Britain, which counted three nationals among the aid workers, a letter signed by more than 600 lawyers piled new pressure on the government to suspend arms export licences to Israel.
Medical charity Doctors Without Borders (MSF) accused Israel of systematically destroying Gaza's healthcare system, describing scenes of carnage that no hospital in the world would be able to handle.
"You get crush injuries to the abdomen, to the thorax; amputations are required for the legs and arms; and on top of that, patients suffer severe burns," its deputy programme manager of the Middle East, Amber Alayyan, said.
In his first call with Netanyahu since the deaths of the employees of US-based charity World Central Kitchen, Biden described the Israeli strike as "unacceptable and called for an "immediate ceasefire".
Biden "made clear the need for Israel to announce and implement a series of specific, concrete, and measurable steps to address civilian harm, humanitarian suffering, and the safety of aid workers", a White House statement said.
"He made clear that US policy with respect to Gaza will be determined by our assessment of Israel's immediate action on these steps."
National Security Council spokesman John Kirby said Washington expected to see action from Israel within the "coming hours and days" but added that US support for Israel's defence remained "iron-clad".
"What we are looking to see and hope to see here in the coming hours and days is a dramatic increase in the humanitarian assistance getting in, additional crossings opened up, and a reduction in the violence against civilians and certainly aid workers," Kirby said.
Democrat Biden is facing growing pressure in an election year over his support for Israel's Gaza war -- with allies pressing him to consider making the billions of dollars in military aid sent by the United States to its key ally each year dependent on Netanyahu listening to calls for restraint.
Pentagon chief Lloyd Austin too expressed "outrage" at the aid workers' killings -- which Israel has admitted to -- in a phone call with his Israeli counterpart Yoav Gallant.
The bodies of the six foreign staff of WCK -- Australian, British, Polish and US-Canadian citizens -- were repatriated from Gaza via Egypt on Wednesday, while the Palestinian employee was laid to rest in Gaza.
Netanyahu has vowed to destroy Hamas, including in the south Gaza city of Rafah, while pledging to move the more than one million civilians in the city out of harm's way first.
Austin said the aid charity "tragedy reinforced the expressed concern over a potential Israeli military operation in Rafah, specifically focusing on the need to ensure the evacuation of Palestinian civilians and the flow of humanitarian aid".
The Israeli army said Gallant and Austin had also "discussed the threat posed by Iran and its proxy activities", after Israel was blamed for a Monday air strike on the Iranian consulate in Damascus that killed seven Revolutionary Guards, two of them generals.
Iran's supreme leader Ayatollah Ali Khamenei vowed in a social media message that "with God's help we will make the Zionists repent of their crime of aggression against the Iranian consulate in Damascus".
The Israeli military said that, after a "situational assessment, it was decided to increase manpower and draft reserve soldiers".
The army also said "leave will be temporarily paused for all combat units".
As Netanyahu has fought the war, he has faced intense domestic pressure from the families and supporters of Israeli hostages still held in Gaza, and from a resurgent anti-government protest movement.
War cabinet member Benny Gantz, a centrist political rival of Netanyahu, has demanded that a snap election be held in September, a call rejected by the premier's right-wing Likud party.
The bloodiest ever Gaza war began with Hamas's October 7 attack, which resulted in the deaths of about 1,170 people in Israel, mostly civilians, according to an AFP tally of Israeli official figures.
Israel's retaliatory campaign has killed at least 33,037 people, mostly women and children, according to the health ministry in Hamas-run Gaza.
Palestinian militants also took more than 250 hostages on October 7, and 130 remain in Gaza, including 34 who the army says are dead.
Amid the heightened tensions, Israeli security services said they had foiled a plot to kill the far-right National Security Minister Itamar Ben Gvir, who heads the Jewish Power party, and to strike other targets.
