US President Donald Trump has threatened to "totally destroy North Korea" if his country is forced to defend itself or its allies, in a highly-combative debut speech to the United Nations General Assembly (UNGA).

Addressing world leaders and representatives from 193 countries gathered in New York, Trump on Tuesday warned that the US would be forced to confront North Korean leader Kim Jong-un if he continued Pyongyang's reckless pursuit of nuclear weapons".

Al Jazeera's James Bays, reporting from the UN headquarters in New York, said that Trump had used "the strongest language you can possibly have in a speech.

"You have never heard a US president saying that in the UNGA, threatening to totally destroy another country," Bays said. "I don't think you have heard any other leader [using this language], despite 72 years of sometimes very controversial bombastic speeches."

READ MORE: UN's Antonio Guterres warns against North Korea war

Trump also attacked Iran in his speech, accusing it of being a "rogue state and a murderous regime". He said the US could not abide by an agreement if it provided cover for the construction of a nuclear programme

The US president addressed the UNGA for about 45 minutes. Here are some of the subjects he covered in his speech.

North Korea

"North Korea's reckless pursuit of nuclear weapons and ballistic missiles threatens the entire world with unthinkable loss of human life.

"It is an outrage that some nations would not only trade with such a regime but would arm supply and financially support a country that imperils the world with nuclear conflict.

"No nation on earth has an interest in seeing this band of criminals arm itself with nuclear weapons and missiles.

"The United States has great strength and patience, but if it is forced to defend itself or its allies, we will have no choice but to totally destroy North Korea.

"Rocket Man is on a suicide mission for himself and for his regime. The United States is ready, willing and able, but hopefully, this will not be necessary."

Iran

"The Iran deal was one of the worst and one-sided transactions the United States has ever entered into."

"The Iranian government masks a corrupt dictatorship behind a false guise of a democracy. It has turned a wealthy party with a rich history and culture into an economically depleted rogue state whose chief exports are violence, bloodshed and chaos.

"The longest suffering victims of Iran's leaders are in fact its own people. Rather than use its resources to improve Iranian lives, its oil profits go to fund Hezbollah and other terrorists that kill innocent Muslims and attack their peaceful Arab and Israeli neighbours.

READ MORE: Iran's Khamenei - Tehran will not bow to US bullying

"This wealth which rightly belongs to Iran's people also goes to shore up Bashar al-Assad's dictatorship, fuel Yemen's civil war and undermine peace throughout the entire Middle East.

"We cannot let a murderous regime continue these destabilising activities while building dangerous missiles and we cannot abide by the agreement if it provides cover for the eventual construction of a nuclear programme.

United States

"Fortunately, the United States has done very well since election day last November 8. The stock market is at an all-time high. A record!

"Unemployment is at its lowest level in 16 years. And because of our regulatory and other reforms, we have more people working in the United States today than ever before. Companies are moving back, creating job growth the likes of which our country has not seen in a very long time.

"And it has just been announced that we will be spending almost $700bn on our military and defence. Our military will soon be the strongest it has ever been."

"As president of the United States, I will always put America first ... We can no longer be taken advantage of, or enter into a one-sided deal where the United States gets nothing in return. As long as I hold this office, I will defend America's interest above all else."