Mr Trump, who was joined on stage by United States vice president Mike Pence, said that millions of Americans across the country celebrate the "inspiring" Irish people on St Patrick's Day. I gave the Prime Minister my ideas on how to negotiate it and I think you would have been successful.
"I hate to see it being, everything being ripped apart right now".
Asked by a reporter if he believes there should be a second public referendum on Brexit in Britain, Trump replied he does not think that would be possible and it would be "unfair to the people who won".
The Irish PM said the most pressing issue facing his country was how to settle questions about the future of the border between Ireland, an European Union member, and Northern Ireland, which won't be.
Trump also lamented he was "surprised at how badly it has all gone from the standpoint of negotiating".
The US President had been due to visit Ireland in 2018 but the trip was ultimately cancelled for scheduling reasons.
He said it is the UK's decision and the most important thing for Ireland is to avoid a hard border and protect the Northern Ireland peace process.
England's Gareth Southgate on squad selection and Declan Rice
On Pickford: "You can look across the squad and say they have had moments where they played well and moments not so well". Burnley goalkeeper Tom Heaton has also been recalled having not featured for his country in almost two years.
British parliament on Tuesday overwhelmingly rejected Prime Minister Theresa May's Brexit deal, throwing the country's Brexit process into further chaos.
The Taoiseach referred to Mr Trump's "Make America Great Again" slogan and said that while the United States had military might and a booming economy, they shouldn't lose sight of what makes America great already - its people and its values.
"I particularly want to thank you for your help with the plant in the west of Ireland where hundreds of jobs were threatened as a result of the Russian sanctions", he stated.
The most concerning element for Ireland, Varadkar said, is that Brexit should not cause any problems in Northern Ireland, which voted to stay in the EU.
"I think it'll be a few years until the United Kingdom sorts itself out", predicted Varadkar. "It is just a great place", he said.
Gardiner rejects Irish concerns about the border and said the issue has been used as a "battering ram" by European Union leadership keen to make Britain a cautionary example to other member states flirting with an exit.
"But it will all work out, everything does, one way or the other".