Over 20 countries to attend Trump's Board of Peace meeting on Thursday

US President Donald Trump's Board of Peace meeting is set to take place on Thursday in Washington, where he will announce that member states have pledged more than $5 billion for reconstruction and humanitarian efforts in Gaza, the White House said.

White House press secretary Karoline Leavitt told reporters on Wednesday that more than 20 countries would participate in the meeting, adding that member states had committed to providing thousands of personnel for an international stabilisation force for Gaza.

Asked about the Vatican's decision not to participate in the initiative, Leavitt called the move "deeply unfortunate".

Leavitt said Trump would chair the first part of Thursday's meeting before departing Washington for a visit to Georgia.

Trump signed documents in Davos, Switzerland, on January 23 establishing the Board of Peace. The board's creation was endorsed by a United Nations Security Council resolution as part of Trump's Gaza plan.

"The president has a very bold and ambitious plan and vision to rebuild and reconstruct Gaza, which is well underway because of the Board of Peace," Leavitt said. "This is a legitimate organisation where there are tens of member countries from around the world."

While regional Middle East powers, including Turkey, Egypt, Saudi Arabia and Qatar, as well as major emerging nations such as Indonesia, have joined the board, global powers and traditional Western US allies have been more cautious.

Cardinal Pietro Parolin, the Vatican's top diplomatic official, on Tuesday said efforts to handle crises should be managed by the United Nations. Pope Leo, the first US pope and a critic of some of Trump's policies, was invited to join the board in January.

Under Trump's Gaza plan, which led to a fragile ceasefire in October, the board was meant to supervise Gaza's temporary governance.

But Trump later said the board, with him as chair, would expand to tackle global conflicts, stirring concerns that the Board of Peace might try to resolve other conflicts around the world and compete with the United Nations. Thursday's meeting is expected to focus solely on Gaza.