US President Donald Trump has issued what he called a "last warning" to Hamas to release the hostages being held in Gaza.

"I am sending Israel everything it needs to finish the job, not a single Hamas member will be safe if you don't do as I say," Trump said in a lengthy post on his Truth Social platform.

It comes just hours after the White House confirmed it is holding direct talks with Hamas over the hostages.

Washington has until now avoided direct engagement with the group, and there is a longstanding US policy against having direct contact with entities it lists as terrorist organisations.

In his social media post, Trump said there would be "hell to pay" if the hostages were not released, while not specifying the nature of the support he was sending Israel.

"Release all of the hostages now, not later, and immediately return all of the dead bodies of the people you murdered, or it is OVER for you," he added.

"For the leadership, now is the time to leave Gaza, while you still have a chance."

He also appeared to threaten civilians: "Also, to the People of Gaza: A beautiful Future awaits, but not if you hold Hostages. If you do, you are DEAD!"

It's not the first time Trump has threatened Hamas. In December, he said there would be "all hell to pay" if hostages were not released by the time he took office.

The post came after Trump met with a group of hostages in the White House who had been recently released under the ceasefire.

Meanwhile, White House press secretary Karoline Leavitt confirmed the US has been negotiating directly with Hamas to try to secure the release of the hostages.

President Trump believed in doing what was in the best interest of the American people, Leavitt told reporters.

The special envoy for hostages, Adam Boehler's work was a "good faith effort to do what's right for the American people", she added.

"Two direct meetings" have taken place between Hamas and a US official, "preceded by several communications", a Palestinian source told the BBC.

Israel said there are still 59 hostages being held in Gaza, with up to 24 believed to be alive. US citizens are also among the captives.

News of the talks was first reported by Axios, which said the two sides were meeting in Qatar to discuss the release of US hostages as well as a wider deal to end the war.

A former US deputy Assistant Secretary of Defence for the Middle East said the US needs to be "more proactive" about getting its citizens back.

Mick Mulroy, who is also an ex-CIA paramilitary officer, added that "it could complicate the Israelis' ability to get their citizens back if not tightly coordinated".

Israel's prime minister's office said in a statement it has "expressed its position" regarding the direct talks, but did not provide any further information.

According to reports, Boehler met with Hamas representatives in the Qatari capital, Doha, in recent weeks.

Hamas has had a base in Doha since 2012, reportedly at the request of the Obama administration.

The small but influential Gulf state is a key US ally in the region. It hosts a major American air base and has handled many delicate political negotiations, including with Iran, the Taliban and Russia.

Alongside the US and Egypt, Qatar has also played a major role in talks to broker a ceasefire between Israel and Hamas in Gaza. (BBC)

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