Hamas handed over more bodies of deceased hostages to Israel on Tuesday, one sign of progress after a number of apparent setbacks in the day since US President Donald Trump touted his plan to end the Gaza war.

The bodies were returned after Israel announced it would cut in half the number of humanitarian aid trucks allowed into Gaza in a move to punish Hamas for what Israel called the militant group's violation of its agreement to transfer remains under the ceasefire deal reached last week.

Meanwhile, re-emergent Hamas fighters demonstrated they were reasserting control in Gaza by deploying hundreds of security forces in the streets and executing several people they accused of collaborating with Israel.

The outlook for Trump's peace plan darkened further when the president threatened Hamas with military strikes unless the militant group disarmed.

"If they don't disarm, we will disarm them. And it will happen quickly and perhaps violently," Trump said at the White House, one day after he spoke before the Knesset in Jerusalem.

Israeli Prime Minister Benjamin Netanyahu has maintained the war cannot end until Hamas surrenders its weapons and cedes control of Gaza, a demand the fighters have rejected.

On Monday, Trump proclaimed the "historic dawn of a new Middle East" to Israel's parliament, as Israel and Hamas were exchanging the last 20 living Israeli hostages in Gaza for nearly 2,000 Palestinian detainees and prisoners.

But the return of 28 dead hostages has remained one of the final details to be worked out in the deal to end more than two years of hostilities that began with Hamas attacks on Israel on October 7, 2023.

Hamas has now handed over eight coffins of dead hostages, leaving at least 19 presumed dead and one unaccounted for still in the Gaza Strip.

It was not immediately clear if the handing over of bodies was sufficient for Israel to restore a full complement of aid deliveries.

Israeli officials said they had decided to restrict aid, allowing only half the agreed number of aid trucks into Gaza starting on Wednesday, and to delay plans to open the southern border crossing to Egypt because Hamas had violated the ceasefire deal by failing to turn over bodies of hostages.

Israel's two-year assault has left much of the enclave in ruins and Gaza City and surrounding areas are suffering from a famine that has afflicted more than half a million Palestinians, creating great need for an expected 600 aid trucks to enter Gaza daily during the ceasefire.

Plans have yet to be implemented to open the crossing to Egypt to let some Gazans out, initially to evacuate the wounded for medical treatment.

Meanwhile, Hamas, which seized Gaza in a brief 2007 civil war, has swiftly reclaimed the streets of Gaza's urban areas following the partial withdrawal of Israeli troops last week.

Gaza residents said Hamas fighters were increasingly visible on Tuesday, deploying along routes needed for aid deliveries.

In a video circulated late on Monday, Hamas fighters dragged seven men with hands tied behind their backs into a Gaza City square, forced them to their knees and shot them from behind, as dozens of onlookers watched from nearby storefronts.

A Hamas source confirmed that the video was taken on Monday and that Hamas fighters participated in the executions. Reuters was able to confirm the location by visible geographic features.

Trump has previously given his blessing to Hamas to reassert some control of Gaza, at least temporarily.

Israeli officials have so far refrained from commenting publicly on the re-emergence of the group's fighters.

Palestinian security officials said dozens of people had been killed in clashes between Hamas fighters and rivals in recent days.

In addition Israel, using aerial drones, killed five Palestinians as they went to check on houses in a suburb east of Gaza City, and an Israeli airstrike killed one person and injured another near Khan Younis, Gaza health authorities said.

Hamas accused Israel of violating the ceasefire.

The Israeli military said it had fired on people who crossed truce lines and approached its forces after ignoring calls to turn back.

Hamas sources told Reuters on Tuesday the group would tolerate no more violations of order in Gaza and would target collaborators, armed looters and drug dealers. (Reuters)