Top US diplomat Marco Rubio and Israeli Prime Minister Benjamin Netanyahu presented a united front Sunday against their common enemies, threatening to "open the gates of hell" on Hamas and "finish the job" against Iran.

The pledges came during a joint address to reporters in Jerusalem, where Rubio began his first Middle East trip as secretary of state in President Donald Trump's new administration.

"Hamas cannot continue as a military or a government force... they must be eliminated," Rubio said of the Palestinian Islamist group that fought Israel for more than 15 months in Gaza until a fragile ceasefire took effect on 19 January.

Standing beside Rubio, Netanyahu said the two allies had "a common strategy," and that "the gates of hell will be opened" if all hostages still held by militants in Gaza are not freed.

The comments came a day after Hamas freed three Israeli hostages in exchange for 369 Palestinian prisoners — the sixth such swap under the ceasefire deal, which the United States helped mediate along with Qatar and Egypt.

Netanyahu's comment echoed one made by Trump ahead of Saturday's swap. Trump had said "all hell" would break loose and that he would call for the truce deal's cancellation if the hostages weren't freed on Saturday.

Israel and Hamas have traded accusations of ceasefire violations.

Adding to strain on the deal, Trump has made a widely condemned proposal to take control of Gaza and relocate its more than two million residents.

"We discussed Trump's bold vision for Gaza's future and will work to ensure that vision becomes a reality," Netanyahu said.

The scheme that Trump outlined earlier this month while Netanyahu was visiting Washington lacked details, but he said it would entail moving Gazans to Jordan or Egypt. 

Trump said Palestinians had "lived a miserable existence" in Gaza, and suggested the coastal territory could be redeveloped into the "Riviera of the Middle East".

'The only plan'

Washington, Israel's top ally and weapons supplier, says it is open to alternative proposals from Arab governments, but Rubio has said that for now, "the only plan is the Trump plan."

The international community, however, including Saudi Arabia and other Arab states, is largely in favour of a two-state solution, with a Palestinian state alongside Israel.

Egyptian President Abdel Fattah al-Sisi on Sunday said the establishment of a Palestinian state was "the only guarantee" of lasting Middle East peace.

Rubio is heading to Saudi Arabia on Monday, and will also visit the United Arab Emirates.

Earlier Sunday, Israel's defence ministry said it had received a shipment of US-made 2,000-pound bombs "released by the Trump administration." The Biden administration had previously blocked a shipment of the munitions over fears they would be used in heavily populated parts of Gaza.

Hamas and Israel are implementing the first, 42-day phase of the ceasefire, which nearly collapsed last week.

"At any moment the fighting could resume. We hope that the calm will continue and that Egypt will pressure Israel to prevent them from restarting the war and displacing people," said Nasser al-Astal, 62, a retired teacher in southern Gaza's Khan Yunis.

Since the truce began last month, 19 Israeli hostages have been released in exchange for more than 1,000 Palestinian prisoners.

Out of 251 people seized in Hamas's 7 October 2023 attack on Israel, which sparked the war, 70 remain in Gaza, including 35 the Israeli military says are dead.

Negotiations on a second phase of the truce, aimed at securing a more lasting end to the war, could begin this week in Doha, a Hamas official and another source familiar with the talks have said.

Netanyahu's office said he would convene a meeting of his security cabinet on Monday to discuss phase two.

Separately, it said he was also dispatching negotiators to Cairo Monday to discuss the "continued implementation" of phase one.

The team would "receive further directives for negotiations on Phase II" after Monday's meeting, the office said.

'Shoulder to shoulder'

On Sunday Rubio said Trump showed "courage and vision" on Gaza, aiming to move past "the same tired ideas of the past."

The Gaza war triggered violent fallout throughout the Middle East, where Iran backs militant groups including in Yemen and Lebanon. 

Israel fought a related war with Hamas's Lebanese ally Hezbollah, severely weakening it. 

There were also limited direct strikes by Iran and Israel against each other.

Rubio called Iran the "single greatest source of instability in the region."

Netanyahu said that with the support of the Trump administration, "I have no doubt that we can and will finish the job" against Iran.

"Israel and America stand shoulder to shoulder in countering the threat of Iran," he said.

The 7 October 2023 attack on Israel resulted in the deaths of 1,211 people, mostly civilians, according to an AFP tally of Israeli official figures.

Israel's retaliatory campaign has killed at least 48,271 people in Gaza, the majority of them civilians, according to figures from the health ministry in the Hamas-run territory that the United Nations considers reliable.

On Sunday, Hamas said an Israeli air strike killed three police officers near south Gaza's Rafah in what the militant group called a "serious violation" of the truce. 

Israel said it had struck "several armed individuals" in south Gaza.

It is at least the second Israeli air strike in Gaza since the ceasefire began.