US President Donald Trump will preside over the first meeting of his Board of Peace on Thursday with unresolved questions on the future of Gaza hanging over an event expected to include representatives from more than 45 nations.

The disarmament of Hamas, the size of the reconstruction fund and the flow of humanitarian aid to the war-battered populace of Gaza are among the major questions likely to test the effectiveness of the board in the weeks and months ahead.

Trump is to address the group at the Donald J. Trump US Institute of Peace - a building in Washington the president recently renamed for himself - and announce that participating nations have raised $5 billion for the reconstruction fund.

The money is expected to be a down payment on a fund that will likely need many more billions. Included in the $5 billion is expected to be $1.2 billion each from two of Washington's Gulf Arab allies, the United Arab Emirates and Kuwait, a US official told Reuters.

Trump's Board of Peace has been controversial. It includes Israel but not Palestinian representatives and Trump's suggestion that the Board could eventually address challenges beyond Gaza has stirred anxiety that it could undermine the UN's role as the main platform for global diplomacy and conflict resolution.

Senior US officials said Trump will also announce that several nations are planning to send thousands of troops to participate in an International Stabilization Force that will help keep the peace in Gaza.

Disarming Hamas militants in order for the peacekeepers to begin their mission remains a major sticking point, and the force is not expected to deploy for weeks or months.

The Palestinian group Hamas, fearful of Israeli reprisals, has been reluctant to hand over weaponry as part of Trump's 20-point Gaza plan that brought about a fragile ceasefire last October in the two-year Gaza war.

"We are under no illusions on the challenges regarding demilitarization, but we have been encouraged by what the mediators have reported back," a senior administration official said.

Most Security Council members not attending

Delegations from 47 countries plus the European Union are expected to attend the event, US officials said. The list includes Israel and a wide array of countries from Albania to Vietnam.

It does not, however, include permanent United Nations Security Council members like France, Britain, Russia and China.

Speakers at the event are expected to include Trump, Secretary of State Marco Rubio, US envoys Steve Witkoff and Jared Kushner, former British Prime Minister Tony Blair, who is expected to have a senior role in the board, U.S. ambassador to the UN Mike Waltz, and High Representative for Gaza Nickolay Mladenov, among other attendees.

A member of the peace board, who declined to be named, said the Gaza plan faces formidable obstacles. Establishing security in the enclave is a precondition for progress in other areas, but the police force is neither ready nor fully trained, said the official.

The official added that a key unresolved question is who would negotiate with Hamas. The peace board’s representatives could do so with countries that have influence over Hamas - notably Qatar and Turkey - but Israel is deeply skeptical of both.

Another major issue is the flow of aid, which the official described as “disastrous” and in urgent need of scaling up. Even if aid surges in, it remains unclear who will distribute it, the official said.