TEL AVIV, Israel — Israel stopped the entry of all goods and supplies into the Gaza Strip on Sunday and warned of “additional consequences” if Hamas doesn’t accept a new proposal to extend a fragile ceasefire, while key mediator Egypt accused Israel of using “starvation as a weapon.”

Hamas accused Israel of trying to derail the ceasefire agreement hours after its first phase ended. It called the decision to cut off aid “cheap extortion, a war crime and a blatant attack” on the truce, which took hold in January after over a year of negotiations. Both sides stopped short of saying the ceasefire had ended.

The first phase, which included a surge in humanitarian assistance after months of growing hunger in the territory, expired on Saturday. The two sides have yet to negotiate the second phase, in which Hamas was to release dozens of remaining hostages in return for an Israeli pullout from Gaza and a lasting ceasefire. Talks should have begun a month ago.

Egyptian Foreign Minister Badr Abdelatty condemned Israel’s decision as “a flagrant and clear violation of humanitarian law,” and called for the immediate implementation of the second phase.

The International Committee of the Red Cross, which has facilitated the releases of hostages and Palestinian prisoners, said the ceasefire has saved countless lives, and “any unraveling of the forward momentum created over the last six weeks risks plunging people back into despair.”

Israel described the new proposal as a U.S. one. There was no immediate comment from the United States, and it was not clear when U.S. envoy Steve Witkoff, expected to visit the region last week, would arrive.

PHOTOS: Israel cuts off Gaza aid to pressure Hamas to accept a new ceasefire proposal

Israeli Prime Minister Benjamin Netanyahu said that under the existing agreements Israel could resume fighting after the first phase if it believes negotiations are ineffective. He said the ceasefire would only continue if Hamas keeps releasing hostages, telling his Cabinet “there will be no free lunches.” He said Israel was “full coordinated” with President Donald Trump’s administration.

The war has left most of Gaza’s population of over 2 million dependent on international aid. Hundreds of aid trucks had entered Gaza daily since the ceasefire began on Jan. 19, easing fears of famine raised by international experts.

But residents said prices doubled as word of the closure spread.

“Everyone is worried,” said Sayed al-Dairi in Gaza City. “This is not a life.”

Fayza Nassar in the heavily destroyed urban Jabaliya refugee camp said the closure would worsen already dire conditions.

“There will be famine and chaos,” she said.

Israel said the new proposal called for extending the ceasefire through Ramadan - the Muslim holy month that began over the weekend - and the Jewish Passover holiday, which ends on April 20.

Under that proposal, Hamas would release half the hostages on the first day and the rest when an agreement is reached on a permanent ceasefire, Netanyahu said.

Hamas warned that any attempt to delay or cancel the ceasefire agreement would have “humanitarian consequences” for the hostages. It reiterated that the only way to free them is through implementing the existing deal.

Hamas has said it is willing to free the hostages all at once in Phase 2, but only in return for the release of more Palestinian prisoners, a permanent ceasefire and the withdrawal of Israeli forces.

An Egyptian official said Hamas and Egypt would not accept a new proposal aimed at returning the remaining hostages without ending the war. The official, who was not authorized to brief media and spoke on condition of anonymity, said mediators were trying to resolve the dispute.

Under the first, six-week phase of the ceasefire, Hamas released 25 Israeli hostages and the bodies of eight others in exchange for the release of nearly 2,000 Palestinians imprisoned by Israel, including some serving life sentences for deadly attacks and others held without charge. Israeli forces pulled back from most of Gaza and Israel allowed a surge of humanitarian aid to enter.

The first phase was marred by repeated disputes.

Israeli strikes killed dozens of Palestinians who the military said had approached its forces or entered areas in violation of the truce. On Sunday, Israel carried out an airstrike on Palestinians it said were planting an explosive device in northern Gaza near the border. Gaza’s Health Ministry said two men were killed and that Israeli fire killed two other people elsewhere.

Hamas paraded most captives - some of them emaciated - before crowds in spectacles that Israel and the United Nations said were cruel and degrading. And it initially returned the wrong set of remains instead of those of a mother who was killed in captivity along with her two young children.

Israel sought to restrict public celebrations over released Palestinian prisoners, and some were freed wearing shirts emblazoned with a Star of David and the phrase “Never forgive, never forget” in Arabic. Some people threw their sweatshirts on the ground and burned them.

Israel imposed a siege on Gaza in the war’s opening days and only eased it under U.S. pressure. U.N. agencies and aid groups accused Israel of not facilitating enough aid during 15 months of war.

The International Criminal Court said there was reason to believe Israel had used “starvation as a method of warfare” when it issued an arrest warrant for Netanyahu last year. The allegation is also central to South Africa’s case at the International Court of Justice accusing Israel of genocide.

Israel has denied the accusations and rejected both court actions as being biased. Israel says it has allowed in enough aid and blamed shortages on what it called the U.N.’s inability to distribute it. Israel accused Hamas of siphoning off aid.

Kenneth Roth, the former head of Human Rights Watch, said Israel as an occupying power has an “absolute duty” to facilitate humanitarian aid under the Geneva Conventions, and called Israel’s decision “a resumption of the war-crime starvation strategy” that led to the ICC warrant.

The war began when Hamas-led militants stormed into southern Israel on Oct. 7, 2023, killing some 1,200 people, mostly civilians, and taking 251 hostage. The militants currently hold 59 hostages, 35 of them believed to be dead.

Israel’s offensive has killed over 48,000 Palestinians, according to Gaza’s Health Ministry. It says more than half of those killed were women and children. It does not specify how many of the dead were combatants.

Israeli bombardment pounded large areas of Gaza to rubble and displaced some 90% of the population.

This story has been corrected to show that 35 of the remaining hostages are believed to be dead, not 32.

Magdy reported from Cairo. Associated Press writer Ellen Knickmeyer in Washington contributed to this report.