U.S. Secretary of State Antony Blinken has delivered some of the Biden administration's strongest public criticism yet of Israel's conduct of the war in Gaza, saying Israeli tactics have meant "a horrible loss of life of innocent civilians" but failed to neutralize Hamas leaders and fighters and could drive a lasting insurgency.

In interviews Sunday with Meet the Press and Face the Nation, Blinken underscored that the United States believes Israeli forces should "get out of Gaza," but also is waiting to see credible plans from Israel for security and governance in the territory after the war.

Hamas has reemerged in parts of Gaza, Blinken said, and "heavy action" by Israeli forces in the southern city of Rafah risks leaving America's closest Mideast ally "holding the bag on an enduring insurgency."

He said the U.S. has worked with Arab countries and others for weeks on developing "credible plans for security, for governance, for rebuilding" in Gaza, but "we haven't seen that come from Israel."

Blinken also said that as Israel pushes deeper in Rafah in the south, a military operation may "have some initial success" but risks "terrible harm" to the population without solving a problem "that both of us want to solve, which is making sure Hamas cannot again govern Gaza."

More than 300,000 Palestinians fled Rafah over the weekend as Israeli forces pushed deeper into the southern city, according to UN estimates. Israel says Rafah is the last stronghold of the Hamas militant group and vowed to launch a full-scale invasion of the city, but the U.S. says a Rafah offensive would jeopardize ceasefire talks.

Some 1.4 million Palestinians — more than half of Gaza's population — had sought refuge in the city.

United Nations human rights chief Volker Türk said in a video statement on Sunday that he cannot see how a "full-scale offensive" in Gaza could be reconciled with international humanitarian law.

LISTEN l The Guardian's world affairs editor Julian Borger on the state of the war:

Blinken worries about 'vacuum filled with chaos'

Israel's conduct of the war, Blinken said, has put the country "on the trajectory, potentially, to inherit an insurgency with many armed Hamas left or, if it leaves, a vacuum filled by chaos, filled by anarchy, and probably refilled by Hamas. We've been talking to them about a much better way of getting an enduring result, enduring security."

Blinken also echoed, for the first time publicly by a U.S. official, the findings of a new Biden administration report to Congress on Friday that said Israel's use of U.S.-provided weapons in Gaza likely violated international humanitarian law. The report also said wartime conditions prevented American officials from determining that with certainty in specific airstrikes.

WATCH l Israeli PM suggests Saudis, U.A.E. could have role in postwar Gaza:

Israeli PM Netanyahu vows to defeat Hamas despite 'disagreements' with U.S.

Israeli Prime Minister Benjamin Netanyahu did an interview with TV personality Dr. Phil about his views on the war with Hamas and what will happen next in Gaza.

"When it comes to the use of weapons, concerns about incidents where given the totality of the damage that's been done to children, women, men, it was reasonable to assess that, in certain instances, Israel acted in ways that are not consistent with international humanitarian law," Blinken said. He cited "the horrible loss of life of innocent civilians."

Blinken urged Israeli Defense Minister Yoav Gallant to allow humanitarian workers to bring aid into Gaza and distribute it on Sunday, according to a State Department recap of their phone call. Israel's current offensive into Rafah has shut down one of the two main border crossings into the territory for a week, and most operations have stopped at the other one after it was targeted by a Hamas rocket attack.

Israel honours victims on Memorial Day

Seven months of fighting and Israeli restrictions on aid deliveries have led to famine in the north of Gaza. Aid organizations say the now nearly total cutoff of food, medicine and fuel and the disruption from the Rafah offensive have humanitarian operations across Gaza on the brink of collapse.

Israel's offensive has killed more than 35,000 Palestinians, according to the health ministry in Gaza. While the health ministry does not distinguish between combatants and civilians in its death tolls, it says the majority of the dead have been women and children.

The war began on Oct. 7 after an attack in Israel led by Hamas that killed 1,200 people, according to Israeli government tallies, including several Canadian citizens. About 250 people were taken hostage, with the Israeli government believing just under 130 are unaccounted for, with several confirmed dead and dozens repatriated after a late November pause in fighting.

On Monday morning, sirens announced two minutes of silence as Israel remembered the victims and the missing in the first Memorial Day since Oct. 7. At a ceremony, Israeli Prime Minister Benjamin Netanyahu vowed once again to defeat Hamas.