US President Donald Trump yesterday warned “bureaucracy” is stopping the United Nations from realising its potential, a barbed message during his first appearance at an institution he once derided as a talking shop, reports AFP from United Nations. Attending a discussion on UN reform, Trump insisted he had always seen the "great potential" of the organisation from a perch "right across the street" at his New York home.

"The United Nations was founded on truly noble goals" he said, adding that "in recent years the United Nations has not reached its full potential, because of bureaucracy and mismanagement."

About 130 world leaders are attending this year's global gathering, but all eyes will be on Trump, whose "America First" agenda has alarmed both allies and foes.

The UN's number one financial backer, the United States has threatened deep cuts to UN funding that Secretary-General Antonio Guterres has said would create an "unsolvable problem" for the world body.

Guterres, who is pushing for an overhaul of the UN bureaucracy, will also address the event at which leaders will sign a pledge of support for reform.

France and Russia have reacted coolly to the US initiative, amid concerns that the US administration is focused more on cost-cutting than improving the UN's performance.

US Ambassador Nikki Haley was a driving force behind a $600-million-dollar cut to the UN peacekeeping budget this year. Haley on Friday pointed to the more than 120 countries that back the US-drafted political declaration on UN reform

as a "miraculous number," showing there is support for a "massive reform package" led by Guterres. On Monday, Trump will hold talks with French President Emmanuel Macron, who will also be making his maiden address at the General Assembly on Tuesday, and with Israeli Prime Minister Benjamin Netanyahu. Both Macron and Netanyahu are expected to raise the future of the Iran nuclear agreement, with the French leader making a strong case for keeping it alive and the Israeli prime minister pushing for its demise.

Trump will also have a working dinner with Latin American leaders that will touch on the crisis in Venezuela. North Korea's nuclear and missile tests will be in the spotlight with foreign ministers set to discuss enforcing sanctions against Pyongyang during a Security Council meeting on non-proliferation on Thursday.