Benjamin Netanyahu has insisted Israel and the United States stand ready to "open the gates of hell" if all Israeli hostages are not released from captivity in Gaza.
The Israeli prime minister made the comments alongside US Secretary of State Marco Rubio a day after his country received a shipment of American made heavy bombs.
The previous Biden administration had blocked the munitions from export to Israel due to concerns over their potential use in Gaza.
The provocative but routine remarks from Mr Netanyahu since the start of the war in Gaza set the scene for negotiations on "phase two" of the ceasefire between Israel and Hamas in the war-ravaged strip.
Those talks are expected to ramp up this week after a fortnight of delays and disputes between the two sides.
Speaking in Jerusalem, Mr Netanyahu said he shared a "common strategy" with US President Donald Trump on the war in Gaza.
"We can't always share the details of this strategy to the public, including when the gates of hell will be opened as they surely will if all our hostages are not released, until the last one of them," he said.
It is Mr Rubio's first trip to the Middle East since taking the position of the US' top diplomat, and he is expected to visit the United Arab Emirates and Saudi Arabia after his meetings in Israel.
The pitch by Mr Trump on the future of Gaza — clearing out Palestinians from the territory and permanently resettling them in other countries, before rebuilding begins — looms large over his tour of the region.
While there is little detail on how the White House plans to enforce the president's vision, Mr Rubio has defended the proposal.
"Not the same tired ideas of the past but something that's bold and something that frankly took courage and vision in order to outline," he said.
"It may have shocked and surprised many, but what cannot continue is the same cycle where we repeat over and over again and wind up in the exact same place."
As Mr Rubio and Mr Netanyahu held talks in Jerusalem, Jordan's Crown Prince Hussein and Egypt's President Abdel Fattah al-Sisi met in Cairo.
The two countries had been named by Mr Trump as resettlement havens for Gazans, but both have rejected the idea.
Arab nations are working on a counter proposal, where rebuilding can occur in Gaza without the permanent displacement of Palestinians.
Hamas says Israeli strikes kill three Gaza policemen
Hamas has accused Israel of breaching the ceasefire in Gaza, saying an air strike killed three policemen near Rafah in the south of the strip on Sunday, local time.
The Hamas run interior ministry said the men were protecting aid deliveries, while Israel said it targeted armed individuals who were moving towards IDF forces in the area.
It is another example of the fragility of the truce between the two sides in Gaza, and the serious challenges facing mediators in trying to negotiate a lasting peace.
Talks on phase two of the ceasefire were meant to begin a fortnight ago, on day 16 of the current agreement, but Mr Netanyahu prioritised a visit to Washington DC.
Last week they were delayed further when Hamas threatened to halt further handovers of hostages over alleged Israeli breaches of the ceasefire — such as restrictions on aid deliveries.
Phase one of the ceasefire lapses on March 2.
On Sunday, the US' Middle East envoy Steve Witkoff said talks on phase two of the deal between Israel and Hamas would continue this week.
Mr Netanyahu said he would also convene his security cabinet on Monday to discuss phase two.
Nineteen of the 33 Israeli hostages slated for release in the initial six-week ceasefire are now free. Eight of those remaining are dead.
There are dozens more who will only be freed if the ceasefire is extended.
As the negotiations continue, Israel is facing accusations of double standards — complaining about the treatment of hostages held by Hamas, while allowing the alleged beating and neglect of Palestinian prisoners and detainees held in Israeli jails.
