UNITED NATIONS — President Donald Trump castigated the United Nations as a feckless institution in a speech to the world body on Tuesday, praising the turn America has taken under his leadership while warning Europe will be ruined if it doesn’t turn away from a “double-tailed monster” of ill-conceived migration and green energy policies.

His roughly hourlong speech before the U.N. General Assembly was both grievance-filled and self-congratulatory as he used the platform to applaud his second-term achievements and lament that some of his fellow world leaders’ countries were “going to hell.”

The address was the latest reminder for U.S. allies and foes that the United States — after a four-year interim under the more internationalist President Joe Biden — has returned to an unapologetically “America First” posture with an antagonistic view toward the United Nations. Trump also sharply criticized the global body for inaction, saying it was filled with “empty words” that “don’t solve wars.”

“What is the purpose of the United Nations?” Trump said. “The U.N. has such tremendous potential. I’ve always said it. It has such tremendous, tremendous potential. But it’s not even coming close to living up to that potential.”

Afterward, Trump attempted to assuage fears from some diplomats by assuring the top U.N. leader that the U.S. remained “100%” supportive of the global body despite his earlier criticism.

“I may disagree with it sometimes, but I am so behind it because the potential for peace at this institution is great,” Trump told Secretary-General Antonio Guterres.

It was another about-face after Trump offered a weave of jarring juxtapositions in his address to the assembly.

He trumpeted himself as a peacemaker and enumerated successes of his administration’s efforts in several hotspots around the globe. At the same time, Trump heralded his decisions to order the U.S. military to carry out strikes on Iran and more recently against alleged drug smugglers from Venezuela and argued that “globalists” are on the verge of destroying successful nations.

Trump touted his administration’s policies allowing for expanded drilling for oil and natural gas in the United States, and aggressively cracking down on illegal immigration, implicitly suggesting more countries should follow suit.

He sharply warned that European nations that have more welcoming migration policies and commit to expensive energy projects aimed at reducing their carbon footprint were causing irreparable harm to their economies and cultures.

“I’m telling you that if you don’t get away from the ‘green energy’ scam, your country is going to fail,” Trump said. “If you don’t stop people that you’ve never seen before that you have nothing in common with, your country is going to fail.”

Trump added, “I love the people of Europe, and I hate to see it being devastated by energy and immigration. This double-tailed monster destroys everything in its wake, and they cannot let that happen any longer.”

Trump also addressed Russia’s war in Ukraine, once again threatening to hit Moscow with “a very strong round of powerful tariffs” if Russian President Vladimir Putin does not come to the table to end the war.