Former FBI director James Comey has voiced his concerns about Donald Trump's leadership and his “zero-tolerance” immigration policy along the US-Mexico border which has seen migrant children separated from their parents.
"My concern about Donald Trump is not actually about his policies," Comey told RTÉ Radio 1's Today with Sean O'Rourke.
He said Trump's attack on American values "threatens the core of our country".
Mr Comey said the separation of migrant children from their parents at the US border is an example of Donald Trump's harmful tactics.
"[It is] a shameful, disgraceful episode in the history of my country," he said. "[It is] utterly inconsistent with who we are as Americans."
Mr Comey said if there is any good to come of putting children in cages, it would be that the American people wake up to the threat to American values and that that should bother Republicans, Democrats and Independents.
Comey said he was concerned when the newly-inaugurated President Trump asked the then FBI director for his loyalty.
"He explicitly asked for my loyalty, which is a shocking thing for anyone who knows America since Watergate," he said.
He said he is saddened that Hillary Clinton feels his actions cost her the American presidency.
"I feel bad that she's carrying around that pain," he said in relation to a quote in her book where she said: "If not for the dramatic intervention of the FBI director in the final days we would have won the White House."
He said that he hopes she has read the part of his book where he discusses his involvement in the investigation into her emails.
"I honestly don't think you can learn about those decisions and walk away thinking we were intending to harm her in some way. You may disagree with the decisions but we made them in good faith. There was no bias, we were trying to do the right thing by the values of our institution," he said.
Listen to James Comey's message to Hillary Clinton here:
Mr Comey is in Dublin to speak at an event at the Irish Film Institute in Temple Bar this evening.
Mrs Clinton, who is also in Dublin today, will be awarded an honorary degree at Trinity College.