A deal between the US and Denmark over Greenland will make Europe safer, Donald Trump has told world leaders as he said he would get the Ukraine war “done”, claiming both sides “have had it”.

In a speech to the United Nations General Assembly in New York, the US president also said Iran faced a choice of reaching an agreement to end the Middle East conflict or face annihilation, as he would “drive them into hell with no chance of survival”.

However, Mr Trump claimed Tehran would not make a pact until after US mid-term elections in November in an apparent attempt to appease domestic voters angered at the higher costs fuelled by the conflict.

He also again levelled the charge that Iran had developed a missile “capable of hitting Europe” as he sought to justify his military intervention.

Washington announced last week that a deal had been reached with fellow Nato member Denmark over Greenland, which had been the focus of a fractious diplomatic standoff after the president made repeated threats to annex the semi-autonomous Arctic territory.

At the UN, Mr Trump hailed it as an “unprecedented agreement regarding the northern frontier of North America”.

He told the gathering: “We will have the complete ability to do what is necessary to defend the American continent and also Europe and other places.”

Despite the international tensions he sparked with his claims over the mineral-rich island, Mr Trump said he looked forward “to working with the wonderful people of Denmark and Greenland”.

He said: “It’s been a great experience, amazing experience, and we’ve really formed a bond in doing it.”

He added: “By expanding America’s footprint in the Arctic and North Atlantic this deal also protects Europe, in addition to America, and greatly protects them. It also very much enhances Nato.”

At the signing of the agreement a short time later, Danish prime minister Mette Frederiksen said the occasion “represents a milestone in our long-standing co-operation”.

Referring in his speech to the Ukraine war, triggered by Russia’s invasion of the country more than four years ago, Mr Trump said: “We’re working very closely with the leaders of Russia and Ukraine, and we will get that one done.

“It’s going to happen, I think, more quickly than people understand.

“They’ve had it – 25,000 young people, mostly soldiers, a month are dying, 25,000 a month.

“And I look at those battlefield pictures, and I really don’t want to see them any more. It’s so horrible to see – 25,000 a month, both sides.”

On the Iran conflict, Mr Trump insisted the US will “get it done one way or the other”.

Speaking about the threat posed by Tehran, he said: “They also made a missile that was capable of hitting Europe, and they were very proud of it.

“I hope the Europeans realise that Iran’s goal was to complete their mad dash to a nuclear bomb from behind this conventional ballistic missile shield.

“If they had succeeded, that wicked regime would have been free to spread terror and death forever, knowing that any attempt to stop them would face an arsenal of nuclear annihilation.”

Despite the war, he claimed the US navy had “recently escorted more than one billion barrels of oil out of the Strait of Hormuz” and that “more oil is flowing than at any point since the start of the war” through the Gulf waterway, over which Iran has imposed a stranglehold since the start of hostilities.

Mr Trump said: “I have a big decision to make.

“Will a deal be made with Iran that lets them rebuild and create a far greater country than it ever was before? Maybe one of the greatest in the Middle East or even the world?

“Or do I annihilate the Islamic Republic and do it quickly, never giving them a chance to kill and destroy people and countries again? Do I drive them into hell with no chance of survival and no hope of future greatness for generations?

“But I believe we’ll make a deal right after the election because it doesn’t make sense for them not to.

“They’re waiting to see how I do in the mid-term election. What they don’t realise is that I’m not running. I did that already and won in a landslide.

“We won in a giant landslide, and I’ll be here for two and a half years. The Republican Party is running and I’ll be helping them.”

Mr Trump added: “We will get it done one way or the other. It’s going to be done. It’s going to be done fast.”

Despite his threats, the president later told reporters that US and Iranian officials had held talks that had lasted three hours.

He said: “It was a very good meeting.”