United Nations Secretary-General Antonio Guterres addresses the opening meeting of the 61st session of the UN Commission on the Status of Women at the UN headquarters in New York March 13, 2017. (Xinhua/UN Photo/Rick Bajornas)

UNITED NATIONS, March 16 (Xinhua) -- UN Secretary-General Antonio Guterres warned on Thursday that U.S. President Donald Trump's proposed budget cuts, believed to severely affect UN funding, could "undermine the impact of longer-term reform efforts" of the world organization, a UN spokesman said here.

"The secretary-general is totally committed to reforming the United Nations and ensuring that it is fit for purpose and delivers results in the most efficient and cost-effective manner," UN spokesman Stephan Dujarric said at a daily news briefing here.

"However, abrupt funding cuts can force the adoption of ad hoc measures that will undermine the impact of longer-term reform efforts," Dujarric said.

"The secretary-general stands ready to discuss with the United States and any other member state how best we can create a more cost-effective organization to pursue our shared goals and values," Dujarric said.

Guterres vowed in taking office in January to reform the United Nations and the U.S. president had called for reform during his campaign.

U.S. President Donald Trump waves with Speaker of the House Paul Ryan (R-WI) after attending a Friends of Ireland reception on Capitol Hill in Washington, U.S., March 16, 2017. (Xinhua/REUTERS)

Earlier Thursday the White House released Trump's 2018 budget blueprint which indicated a 28 percent cut in funds for the U.S. State Department, USAID and the United Nations, dropping from 54 billion U.S. dollars to 39 billion U.S. dollars.

The U.S. ambassador to the United Nations, Nikki Haley, described in a statement issued on Thursday how she has been working with Guterres to "reform the peacekeeping process and UN management" as promised during the campaign.

"In many areas, the UN spends more money than it should, and in many ways it places a much larger financial burden on the United States than on other countries," she said. "I look forward to working with Members of Congress to craft a budget that advances U.S. interests at the UN, and I look forward to working with my UN colleagues to make the organization more effective and efficient."

The United States was assessed 22 percent of the 5.4 billion U.S. dollars UN regular two-year 2016-2017 budget and 28 percent of the 7.87 billion U.S. dollars July 2016-June 2017 peacekeeping budget. The percentages are based on estimates of gross national income.