"Yet in recent years, the United Nations has not reached its full potential because of bureaucracy and mismanagement," Trump said at the forum titled, “Reforming the United Nations: Management, Security, and Development.”
Trump said increases in the U.N.'s budget and staffing haven't yielded results.
"We seek a United Nations that regains the trust of the people around the world," Trump said. "In order to achieve this, the United Nations must hold every level of management accountable, protect whistleblowers and focus on results rather than on process."
"We must ensure that no one, and no member state, shoulders a disproportionate share of the burden, and that's militarily or financially," he said.
The president also referenced one of his private properties, Trump World Tower, saying he purposely built it adjacent to the U.N. headquarters in New York City.
"I actually saw great potential right across the street to be honest with you, and it was only for the reason that the United Nations was here that that turned out to be such a successful project," Trump joked.
Speaking to the press later in the day ahead of a meeting with Israeli Prime Minister Benjamin Netanyahu, Trump expressed optimism at the potential to broker peace between the Israelis and Palestinians. He was also asked about the future of the Iran nuclear deal and whether he intended for the U.S. to remain a party to the agreement.
"You will see very soon," Trump said in response.
Meeting with the leaders of Latin American nations at dinner Monday evening, Trump relayed his earlier conversation with President Xi of China on a variety of topics, including North Korea.
"We discussed some of the obvious things, and we discussed trade, and we also discussed a place called North Korea," Trump said, before changing the subject to unrest in Venezuela.
"We're here to discuss the growing crisis in Venezuela," Trump said to the delegation of leaders from Central and South America. "The socialist dictatorship of Nicolas Maduro has inflicted terrible misery and suffering on the good people of that country."
Regarding recent sanctions against the Venezuelan government, Trump offered, "We are prepared to take further action if the government of Venezuela persists on a path to imposing authoritarian rule on the Venezuelan people."
Trump will make his first full remarks to the U.N. General Assembly on Tuesday.