Israeli hostages released in the past week by Hamas in Gaza have called for the immediate release of the remaining captives, a day after a temporary truce that had allowed scores to come home broke down.
Tens of thousands gathered at a rally in Tel Aviv outside Israel's defence headquarters on Saturday, where they cheered Yelena Trupanov, 50, standing on a stage just two days after being freed.
"I came to thank you because without you I wouldn't be here. Now we must bring back my (son) Sasha, and everyone. Now," she told the crowd.
Similar pleas from other released hostages were shown on video.
A seven-day truce, during which Hamas had released more than 100 hostages, collapsed on Friday.
Throughout Saturday morning, a steady stream of wounded people were carried into the Nasser Hospital in Khan Younis, some receiving treatment on the floor. Gaza health officials said 650 had been wounded since the truce collapsed.
The head of the International Committee of the Red Cross said the renewed fighting was intense.
"It's a new layer of destruction coming on top of massive, unparalleled destruction," Robert Mardini told Reuters in Dubai.
With conditions inside Gaza reaching "breaking point," in Mr Mardini's words, the first aid trucks since the end of the truce entered from Egypt through the Rafah crossing, Egyptian security and Red Crescent sources said. Some 100 trucks passed through, carrying food, water and medical supplies, the sources said.
Israel said on Saturday it had recalled a Mossad intelligence agency team from Qatar, host of indirect negotiations with Hamas, accusing the Palestinian faction of reneging on a deal that would have freed all children and women held hostage.
More than 240 people - Israelis and foreign nationals - were abducted to Gaza on October 7 by Hamas militants who burst through the border with Israel and killed 1,200 people, according to local authorities.
Israel, vowing to wipe out Hamas, responded with a bombing campaign and ground offensive that has destroyed large areas of Gaza and killed more than 15,000 people, according to the health ministry in the Hamas-run enclave.
The rally in Tel Aviv came as US Defense Secretary Lloyd Austin delivered his strongest remarks to date on Saturday over Israel's need to protect civilians in Gaza.
He called civilians the centre of gravity in Israel's war with Hamas and warned over the risks of their radicalisation.
Mr Austin, in remarks to the Reagan National Defense Forum in Simi Valley, California, said he has personally pushed Israeli leaders to avoid civilian casualties, to shun "irresponsible rhetoric" and to prevent violence by settlers in the West Bank.
He also said he's pressed Israel to dramatically expand Gaza's access to humanitarian aid, adding that he expected more deliveries of aid "in the days ahead".
"In this kind of a fight, the center of gravity is the civilian population. And if you drive them into the arms of the enemy, you replace a tactical victory with a strategic defeat," Mr Austin said, drawing on his experience as a four-star general overseeing the battle against Islamic State militants.
"So I have repeatedly made clear to Israel's leaders that protecting Palestinian civilians in Gaza is both a moral responsibility and strategic imperative."
Meanwhile US Vice President Kamala Harris said too many innocent Palestinians had been killed in Gaza.
Speaking in Dubai, Mrs Harris said Israel had a right to defend itself, but international and humanitarian law must be respected and "too many innocent Palestinians have been killed."
"Frankly, the scale of civilian suffering, and the images and videos coming from Gaza, are devastating," she told reporters.
Prime Minister Benjamin Netanyahu, holding a news conference in Tel Aviv later on Saturday, said Israel was continuing to work in coordination with the US and international organisations to define "safe areas" for Gaza civilians.
"This is important because we have no desire to harm the population," Mr Netanyahu said. "We have a very strong desire to hurt Hamas."
Mrs Harris also sketched out a US vision for post-conflict Gaza, saying the international community must support recovery and Palestinian security forces must be strengthened.
"We want to see a unified Gaza and West Bank under the Palestinian Authority, and Palestinian voices and aspirations must be at the center of this work," she said, adding that Hamas must no longer run Gaza.
Under aerial bombardment from Israel, people sheltering in the south of the Gaza Strip after fleeing their homes earlier in the war said on Saturday they had nowhere safe to go now.
The city of Khan Younis is the focus of Israeli air strikes and artillery fire in a new phase of the war after fighting resumed on Friday following the collapse of a week-long truce.
Its population has swelled in recent weeks as several hundred thousand people from the northern Gaza Strip have fled south.
Some are camping in tents, others in schools, while some are sleeping in stairwells or outside the few hospitals operating in the city.
A World Health Organisation official said on Friday that one of the hospitals was "like a horror movie" as hundreds of wounded children and adults waited for treatment.