UNITED NATIONS (Reuters) - U.S. President Donald Trump, a frequent critic of the United Nations, will seek to gather global support for reforming the world body when he hosts an event at U.N. headquarters in New York on Sept. 18, a day before he formally addresses the 193-member organization.

FILE PHOTO: U.S. President Donald Trump is seated in the Oval Office at the White House in Washington, U.S., August 28, 2017. REUTERS/Kevin Lamarque

Countries will be invited to attend Trump’s function if they sign on to a U.S.-drafted 10-point political declaration backing efforts by U.N. Secretary-General Antonio Guterres “to initiate effective, meaningful reform,” according to a draft of the political declaration seen by Reuters on Friday.

Trump has complained that the U.S. share of the world body’s budget is unfair, pushed to slash funding and described it as a “club for people to get together, talk and have a good time.”

Trump, who took office in January, has since described U.S. funding as “peanuts” compared to the important work of the organization.

The United States is the biggest U.N. contributor, providing 22 percent of its $5.4 billion biennial core budget and 28.5 percent of its $7.3 billion peacekeeping budget. The contributions are agreed on by the 193-member General Assembly.

Trump, Guterres, who also took office in January, and U.S. Ambassador to the United Nations Nikki Haley are scheduled to speak at the Sept. 18 event, diplomats said.

The draft political declaration states: “We support the secretary-general in making concrete changes in the United Nations system to better align its work on humanitarian response, development and sustaining peace initiatives.”

“We commit to reducing mandate duplication, redundancy and overlap, including among the main organs of the United Nations,” the draft declaration reads.

The United States also is reviewing each of the U.N. peacekeeping missions as annual mandates come up for Security Council renewal in a bid to cut costs. The United States is a veto-wielding council member, along with Britain, France, Russia and China.

Haley has said there is “a lot of fat around the edges and some abuses that happen at the U.N. but I do think it is very important that we make the most of it.”

Ethiopia, which is president of the 15-member Security Council for September, said on Friday it would hold a high-level council meeting on peacekeeping reform on Sept. 20 that will be chaired by Ethiopian Prime Minister Hailemariam Desalegn.

Ethiopian U.N. Ambassador Tekeda Alemu told reporters it was unclear if Trump would attend the meeting, which would be his first appearance in the Security Council, but that he expected about 10 heads of state or government to be present.