LONDON — If Hamas doesn’t return Israeli hostages by Saturday afternoon, “the ceasefire will be terminated,” Israeli Prime Minister Benjamin Netanyahu said Tuesday in a statement following a meeting with his security cabinet.

“The decision that I passed unanimously in the cabinet is this: If Hamas does not return our hostages by Saturday afternoon — the ceasefire will be terminated, and the IDF will return to intense fighting until Hamas is finally defeated,” Netanyahu said.

Netanyahu is demanding all nine living Israeli hostages who were supposed to be released during phase one of the ceasefire deal now be released in the next few days, an Israeli official told ABC News. Hamas violated the agreement; therefore, there will be no progress in the further implementation of the agreement or in negotiations on the second phase of the deal without the return of Israeli hostages, according to the official.

Netanyahu’s statement comes after President Donald Trump warned that “all hell is going to break out” unless Hamas releases all remaining hostages from Gaza by Saturday, following the group’s announcement it would delay the latest planned release after accusing Israel of violating the ceasefire agreement.

Trump told reporters in the Oval Office on Monday that it would be “appropriate” to abandon the ceasefire unless all hostages are freed. “I would say, cancel it and all bets are off and let hell break out,” he said.

The president dismissed the “drips and drabs” process set out in the January deal that slated small groups of hostages for release during the three-phase ceasefire, in exchange for Israel freeing Palestinian prisoners and withdrawing its forces from parts of Gaza.

“I would say Saturday at 12, we want them all back,” Trump said. “I’m speaking for myself. Israel can override it. But from myself, Saturday at 12 o’clock, and if they’re not, they’re not here, all hell is going to break out.”

In response, senior Hamas official Sami Abu Zuhri said Trump “must remember there is an agreement that must be respected,” in a statement cited by Reuters. “The language of ‘threats’ has no value and only complicates matters,” Zuhri added.

The president also warned that those hostages still being held in Gaza may not be in good physical condition.

“Who knows? Are they alive? Are they not alive? But I saw the condition when I saw the condition of the last ones that came out,” Trump said. “They’re not going to be alive right now, based on what I saw over the last two days, they’re not going to be alive for long.”

Trump suggested Hamas had released the healthiest captives first. “They’ve got more to send out, and they probably feel that they can’t do that, because it’s not going to make them look very good,” he said.

On Tuesday, it was announced that the oldest hostage taken during the Oct. 7, 2023, attack — Shlomo Mantzur, 86 — had been killed that day. Mansour’s death was announced by the Kibutz Kissufim where he lived and was later confirmed by the Israel Defense Forces.

Trump’s latest assertion followed Hamas’ Monday announcement that it would delay the next scheduled release of hostages, planned for Saturday.

In a statement, Hamas said the postponement was intended as a “warning message” to Israel, which it said had repeatedly violated the terms of the January ceasefire deal.

Hamas accused Israel of preventing the return of displaced Gazans to the north of the strip, blocking the planned influx of humanitarian aid and continuing to kill “many” Palestinians despite the pause in fighting.

Israeli Defense Minister Israel Katz said he instructed the IDF to prepare at the “highest level of alert” in response to Hamas’ announcement.

Following the meeting of his security cabinet on Tuesday, Netanyahu instructed the IDF to “reinforce forces in and around the Gaza Strip and to prepare for any scenario” if Hamas does not release “the Israeli hostages this coming Saturday,” an Israeli official told ABC News.

The meeting lasted about four hours and was “thorough and in-depth,” the official said.

All the cabinet members expressed support for Trump’s statement that Israeli hostages should be released by Saturday at noon and for his “revolutionary vision for the future of Gaza,” the official added.

There have so far been five rounds of exchanges between Hamas and Israel since the conflict began. Thirty-three Israeli hostages are expected to be released as part of the first phase of the ceasefire agreement due to last six weeks. The agreement was reached on Jan. 15.

The ceasefire turbulence comes as Trump continues to promote his controversial plan to permanently relocate Gaza’s population — around 2 million people — to other regional nations.

The president said during a taped Fox News interview — parts of which were released on Monday — that Gazans resettled outside of the strip would not be allowed to return to the territory, which he has said will be “a real estate development for the future.”

Pressed on his remarks in the Oval Office on Monday, the president did not repeat his assertion that Palestinians would not be given the right to return, but continued to insist that Gazans would not want to live in the devastated territory.

“We’ve spoken to a lot of Palestinians,” Trump said. “They would love to leave Gaza if they could find a place to be. And I’ve spoken to various leaders of various countries in the not so distant area from where we’re talking about the Gaza Strip, and I think they were very positive about providing land.”

“What we need is land, and if we could build a nice place for people to live safely, everybody in Gaza would do it,” Trump said. “You’re going to see that they all want to leave,” he claimed.

The president has found little foreign backing for his plan, with key regional partners like Egypt, Jordan and Saudi Arabia all rejecting the proposal. Trump has suggested that those countries should help resettle Gazans on their territory.

Jordan has served as a humanitarian lifeline for civilians in Gaza throughout the Israel-Hamas conflict and already hosts millions of registered Palestinian refugees.

The president told reporters on Monday he could “conceivably” withhold billions of dollars in aid to Egypt and Jordan to coerce them into agreeing to host Palestinians displaced from Gaza.

The president will host Jordanian King Abdullah II at the White House on Tuesday. “I do think he’ll take, and I think other countries will take also,” Trump said of Abdullah when asked if he would accept ejected Palestinians. “They have good hearts, I think they’ll take,” he added.

Hamas has rejected Trump’s Gaza plan as “absurd.” In a statement, the group said the president’s comments “reflect a profound ignorance about Palestine and the region. Gaza is not a piece of real estate to be bought and sold; it is an inseparable part of our occupied Palestinian land.”

Nearly 400,000 people have already returned to the north since the beginning of the ceasefire, according to Gazan authorities. Palestinians interviewed by ABC News said they yearn to rebuild Gaza for themselves, the only place they say they have or will ever call home.

Netanyahu, meanwhile, framed Trump’s proposal as “a totally different vision, a much better one for the state of Israel.”

Netanyahu — who met with Trump at the White House last week — described the plan as “revolutionary, creative — and we’re discussing it. He is very determined to carry it out. It opens up many opportunities for us.”

ABC News’ Sarah Kolinovsky, Will Gretsky, Joe Simonetti, Jordana Miller and Shannon Kingston contributed to this report.