Israel bombarded the overcrowded Gaza city of Rafah, where it has launched a ground incursion, as talks resumed Wednesday in Cairo aimed at agreeing the terms of a truce in the seven-month war.
Despite international objections, Israel sent tanks into Rafah on Tuesday and seized the nearby crossing into Egypt that is the main conduit for aid into the besieged Palestinian territory.
The White House condemned the interruption to humanitarian deliveries, with a senior US official later revealing Washington had paused a shipment of bombs last week after Israel failed to address US concerns over its Rafah plans.
The Israeli military said hours later it was reopening another major aid crossing into Gaza, Kerem Shalom, as well as the Erez crossing.
But the UN agency for Palestinian refugees, UNRWA, said the Kerem Shalom crossing -- which Israel shut after a rocket attack killed four soldiers on Sunday -- remained closed.
It came after a night of heavy Israeli strikes and shelling across Gaza. AFPTV footage showed Palestinians scrambling in the dark to pull survivors, bloodied and caked in dust, out from under the rubble of a Rafah building.
"We are living in Rafah in extreme fear and endless anxiety as the occupation army keeps firing artillery shells indiscriminately," said Muhanad Ahmad Qishta, 29.
"Rafah is a witnessing a very large displacement, as places the Israeli army claims to be safe are also being bombed," he told AFP.
Al-Ahli hospital said a strike on an apartment in devastated Gaza City killed seven members of the same family and wounded several other people.
An emergency doctor working in Rafah and neighbouring Khan Yunis said that with humanitarian access compromised, the health situation in the southern cities was "catastrophic".
"The smell of sewage is rife everywhere," said Doctor James Smith. "It's been getting worse over the course of the last couple of days, obviously worse with the hot weather."
The Gaza war was sparked by Hamas's unprecedented October 7 attack on Israel, which resulted in the deaths of more than 1,170 people, mostly civilians, according to an AFP tally of Israeli official figures.
Israel in response vowed to crush Hamas and launched a military offensive that has killed at least 34,789 people in Gaza, mostly women and children, according to the Hamas-run territory's health ministry.
Militants also took around 250 people hostage, of whom Israel estimates 128 remain in Gaza, including 36 who are believed to be dead.
Talks aimed at agreeing a ceasefire resumed in Cairo on Wednesday "in the presence of all parties", Egyptian media reported.
A senior Hamas official said the latest round of negotiations would be "decisive".
"The resistance insists on the rightful demands of its people and will not give up any of our people's rights," he told AFP on condition of anonymity because he was not authorised to speak publicly on the negotiations.
The official had previously warned it would be Israel's "last chance" to free the scores of hostages still in militants' hands.
Mediators have failed to broker a new truce since a week-long ceasefire in November saw 105 hostages freed, the Israelis among them in exchange for Palestinian prisoners held by Israel.
Qatar, which has been mediating between the two sides, appealed "for urgent international action to prevent Rafah from being invaded and a crime of genocide being committed".
Israel's seizure of the Palestinian side of the Rafah crossing came after Hamas said it had accepted a truce proposal -- one Israel said was "far" from what it had previously agreed to.
Israeli Prime Minister Benjamin Netanyahu described the operation as "a very important step" in denying Hamas "a passage that was essential for establishing its reign of terror".
Hours later, a senior US administration official speaking on condition of anonymity said Washington had "paused one shipment of weapons last week" after Israel failed to address its concerns over the Rafah incursion, which the United States has vocally opposed.
The shipment had consisted of more than 3,500 heavy-duty bombs, the official said.
It was the first time President Joe Biden had acted on a warning he gave Netanyahu in April that US policy on Gaza would depend on how Israel treated civilians.
The US official said Washington was "especially focused" on the use of the heaviest 2,000-pound (907 kilogram) bombs "and the impact they could have in dense urban settings".
The Pentagon, meanwhile, said the US military had completed construction of an aid pier off Gaza's coast, but weather conditions meant it was currently unsafe to move it into place.
Defence Minister Yoav Gallant said Israel might "deepen" its Gaza operation if negotiations failed to bring the hostages home.
"This operation will continue until we eliminate Hamas in the Rafah area and the entire Gaza Strip, or until the first hostage returns," he said.
Egypt and Qatar have taken the lead in the truce talks, with Hamas saying Monday it had told officials from both countries of its "approval of their proposal regarding a ceasefire".
Hamas member Khalil al-Hayya told the Qatar-based Al Jazeera news channel the proposal involved a complete Israeli withdrawal from Gaza, the return of Palestinians displaced by the war and a hostage-prisoner exchange, with the goal of a "permanent ceasefire".
Netanyahu's office called the proposal "far from Israel's essential demands", but said the government would still send negotiators to Cairo.
But Netanyahu had repeatedly vowed to send in ground troops regardless of any truce, saying Israel needs to root out remaining Hamas forces.
Aid groups have warned that the coastal "humanitarian area" of Al-Muwasi -- where Israel's military told civilians to move before it launched its Rafah operation -- is unprepared to handle the influx.
