The president, who earlier set out his hopes for a "large scale" US-UK trade deal, added that: "I'm not sure anybody knows" what was happening with Brexit.
He said: "We're talking to them about trade".
"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.
After telling reporters he would stay in his lane and avoid commenting on the contentious British exit from the European Union, U.S. President Donald Trump on Thursday immediately did just the opposite. "I regret that Brexit's happening and the United Kingdom was a really important part of the European Union". Mr Murphy said, 'Brexit, and the uncertainty surrounding it, poses unique and hard challenges for Ireland and Irish business.
In his time on stage Varadkar praised Trump, saying that the President had promised to "Make America Great Again", and that "we can already see some of the results of that", pointing to the American economy as an example of this. "But I think it could have been negotiated in a different manner".
"And people laughed when I predicted it, and they won by about two points", Trump said.More news: Beto O'Rourke takes heat for website's different messages in different languages
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Speaking on Thursday, Trump then took aim at the possibility of a second referendum on leaving the European Union, which he deemed "unfair" on those who had campaigned successfully for Brexit in 2016.
Prior to the breakfast, Varadkar said differences between their administrations' views on gay rights are clear, but that the two countries have a good working relationship, according to the Independent.
MPs have rejected May's withdrawal agreement by huge margins twice and will next vote on delaying Brexit on Thursday night.
In a tweet, Varadkar said it was "great to be back here for a really warm reception".
"The Irish government has played a very adversarial role", Gardiner said. Pence attempted the Irish leader's formal title, calling him "Taoiseach Varadkar".
"The United States and the Republic of Ireland have such close ties that it's unlikely that anything permanently damaging would happen", McMahon said. Varadkar said he appreciates what the president has done for his country economically. But it will all work out.