"In order for peace to be within our grasp, we must first improve the conditions on the ground to create hope and opportunity", White House envoy Jason Greenblatt told the conference.
The Times characterized the summit as "unusual", as it was attended by a representative of Israel, Maj.
The UN said Wednesday about $540 million is needed for humanitarian relief in the Palestinian territories in 2018.
"Only through dialogue and agreement will sustainable progress be made to also include the people of Gaza".
Jared Kushner, a senior adviser to Trump who is overseeing the Israeli-Palestinian peace-process for the White House, gave a two-hour presentation to the attending countries, officials said, but the potential United States peace plan was not addressed.
A senior administration insisted that many projects could be implemented without assistance of the Palestinian Authority, but the goal was to have it ultimately engage in the multi-lateral process. Palestinians are angered at Mr. Trump's decision late a year ago to recognize Jerusalem as the capital of Israel, and to move the USA embassy there from Tel Aviv.
While a number of proposed projects to help Gaza do not require the participation of the PA, an official of the United States government said that it would not be "an ideal situation". "The attendees yesterday discussed concrete proposals for finding realistic, effective approaches to the challenges Gaza now faces". "A great deal of time was spent discussing Hamas's failures in Gaza and the need for the Palestinian Authority to govern Gaza". Two of its three entry points are blockaded by Israel due to national security concerns.