The annual St Patrick's Day Oval Office meeting was dominated by the ongoing war in Iran.
After a short initial dialogue on Irish-US relations and "historic connections", other moments included US President Donald Trump saying he would try to visit Doonbeg for the Irish Open and Taoiseach Micheál Martin defending criticism of British Prime Minister Keir Starmer.
Iran would have hit Europe but maybe not Ireland, says Trump
Donald Trump claimed that the US had prevented "nuclear holocaust" by bombing Iran.
He told reporters in the Oval Office: "I said Iran was a big threat to this country, to this world of ours, and turned out I was right."
He added: "You can't let them have a nuclear weapon. If they got a nuclear weapon, I would say they would have used it within 24 hours after having it.
"And they would have had it if we didn't bomb them out from the great raid with the B2 bombers.
"Eight months ago or so, you would have had a nuclear war in the Middle East and maybe beyond," he said.
Turning to Mr Martin, he said: "I think it would have hit Europe, maybe not Ireland, but it would have hit Europe."
He added: "It is big enough - you would have been affected."
'This was a great test' of NATO relationship
President Trump also said he is "disappointed" with NATO, but that he was not currently rethinking his relationship with the alliance.
"I've long said that I wonder whether or not NATO would be there for us, so this was a great test, because we don't need them, but they should have been there."
He said: "We help other countries and when they don't help us, I mean, it's certainly something that we should think about."
Mr Trump also said the US does not need any help in the Strait of Hormuz.
Asked what assistance the US needed from NATO allies, Mr Trump said: "We don't need any help actually."
Taoiseach defends Keir Starmer
Donald Trump said British Prime Minister Keir Starmer made a "big mistake" in his response to US calls for support in the war with Iran.
"I'm disappointed with Keir - I like him, I think he's a nice man, but I'm disappointed," Mr Trump said.
He also said that "unfortunately Keir is not Winston Churchill".
However, the Taoiseach defended the British prime minister, saying: "I do believe that he is a very earnest, sound person who I think you have the capacity to get on with and you've got on with before.
"And you got on with other European leaders as well and I think you have that capacity again," Mr Martin said.
Mr Martin said that the relationship between the US and Europe was very important and though they had had "issues over the last year or two" they had "settled them".
He added that the British-Irish relationship was very important and that Mr Starmer has done a lot to reset it.
"Everyone accepts that you cannot have a rogue state with a nuclear weapon" and that Iran was "a sponsor of terrorism", he added.
He said that Ireland had its own conflict "that went on for 30 years" and that the country had learned a lot from that about how to bring about peace.
"Our hearts go out to the Iranian people who have been repressed and suppressed for so many years," he said.
'I'm not afraid of anything'
Asked if he was afraid that a ground invasion of Iran would be a repeat of the US-Vietnam war, Mr Trump said: "I'm really not afraid of anything."
Trump considering September visit to Ireland for Irish Open
The St Patrick's Day meeting began with dialogue on US-Irish relations.
The Taoiseach raised the Irish heritage of 23 former US presidents. Mr Trump said the two leaders would be discussing trade and possibly tariffs.
On a possible Irish visit, President Trump said he is "going to try" to attend the Irish Open golf tournament when it is hosted at the Doonbeg course he owns in Co Clare in September.
"You have a tremendous golf tradition, and it was chosen for the Irish Open, which is a big deal. That's a big event," he said.
"Everybody wants me to be there. You (Mr Martin) just said, 'I hope you're going to go'.
"We're going to try. We are going to try. But it would be an honour.
"But it was a great honour to be chosen. They only choose the best courses in the world for the, you know, for the big Opens – it's one of the big ones," Mr Trump said.
