Donald Trump has called on nations to unite to isolate Tehran and bring down global energy prices, as he gave a bellicose defence of his administration’s foreign policy and decision to strike Iran.

“I call on all nations to help to enforce the complete economic isolation of Iran,” Trump said in a speech to the UN general assembly on Tuesday. “If we stand united, we will soon see a world free of the last 51-year menace of Iranian terror … and oil prices will come plummeting down even lower than they were at the start of the conflict.”

Trump’s call for international unity on Iran – he also said he may “annihilate” the country – comes as numerous US allies have complained about soaring energy prices and growing international instability during his US administration.

On the first day of the high-level week of the UN general assembly in New York, Trump also reiterated that the US would not seek to rein in the development of artificial intelligence, seeking to rebrand it as “superintelligence” and saying warnings about the threats from out-of-control AI development were a “hoax”.

“I’m ⁠not going to ​stifle growth ​of something ​that will be bigger ​than ‌the ​Industrial ​Revolution,” he said.

In an address that mostly rehashed his stump speech talking points, Trump announced that the US would build two new military bases in Greenland as part of an agreement with the government of Denmark, after a year of geopolitical haggling that has unsettled the Nato alliance.

“We will have the complete ability to do what is necessary to defend the American continent, and also Europe and other places,” Trump said in announcing the two “major” military bases. “No US adversary will ever be permitted to establish a military presence in Greenland any more, or make sensitive investments there without our express written approval.”

He denied that the US was running short of critical munitions (“we have more munitions than we could ever possibly even think of using”), attacked the international criminal court as a “rogue organisation” and claimed once again that he was close to settling the war in Ukraine.

But this was a less bellicose speech than the one he gave last year, when he excoriated the UN and told European allies that their countries were “going to hell” because of their migration policies. At one point on Tuesday, he stopped and turned around to thank the UN security council for condemning Iranian attacks on shipping in the strait of Hormuz.

During the speech, he repeated a threat to destroy Iran, which he has made dozens of times since the US and Israel launched joint strikes in February.

“I have a big decision to make: will a deal be made with Iran that let them rebuild and create a far greater country than ever was before,” he said. “Or do I annihilate the Islamic republic and do it quickly, never giving them a chance to kill or destroy people and continents?”

Trump denied that he was under political pressure to end the war and said the midterm elections would have absolutely no influence on his decision-making around the conflict.

“They’re waiting to see how I do in the midterm election. What they don’t realise is that I’m not running,” he said. “It doesn’t even enter my mind. The only thing that does is that Iran will never have a nuclear weapon.”

Iran has maintained a stranglehold over energy shipping through the strait of Hormuz since early in the war, and global oil prices have also been driven up by the conflict between Russia and Ukraine, where Kyiv has successfully targeted Moscow’s refining capacity.

Trump defended the US move to arrest the former Venezuelan president Nicolás Maduro in a midnight raid, and the subsequent oil deal he struck with Delcy Rodríguez, Maduro’s successor, who has proved much more amenable to US demands and agreed to a deal sharing the country’s vast oil wealth with the US. “To the victor belong the spoils,” Trump said.

Trump’s New York itinerary is a crib sheet of the ways that his presidency has upended global politics in the last two years. After his speech, Trump signed an agreement with Denmark over the future of Greenland, which Trump has claimed could be dominated by Russia and China despite few signs that was the case.

Later, he is expected to meet the Ukrainian leader, Volodymyr Zelenskyy, whom he is expected to press along with Russia to conclude an energy truce to help assuage soaring prices on diesel mainly prompted by Tehran’s closure of the strait of Hormuz.

Trump will also meet Gulf leaders, who have been affected by Iran’s retaliation to the joint US-Israeli attack, and then will have a pull-aside with the US-backed Rodríguez of Venezuela, another major oil exporter.