The Taoiseach has said he disagrees with US President Donald Trump, who described the European Union as "weak" and accused member states of letting Ukraine fight "until they drop".
Mr Trump made the claims in an interview with Politico, in which he also suggested "decaying" European countries had failed to control migration.
Speaking in Dublin, Micheál Martin said: "Europe is strong, not weak."
He said that "new challenges" had emerged, when it came to defence and security, but he was "confident" they would be overcome.
The Taoiseach added that the EU was amongst the "strongest in the world" when it came to trade, and suggested the recent deal with the US recognises that fact.
He said the response to the Covid-19 pandemic was another example of EU strength.
European Council President Antonio Costa said the EU and US were allies and, as such, Washington should not "interfere" with the internal matters of the bloc.
He said: "Allies must act as allies."
Mr Trump's latest broadside comes days after his administration's new national security strategy sparked alarm by calling for the cultivation of "resistance" in the EU against liberal migration policies.
Asked whether European countries would not remain US allies if they failed to embrace his administration's policies on the issue, Mr Trump replied that "it depends."
"I think they're weak, but they also want to be so politically correct," Mr Trump said.
He listed countries including Britain, France, Germany, Poland and Sweden that he said were being "destroyed" by migration, and launched a new attack on the "horrible, vicious, disgusting" Sadiq Khan, London's first Muslim mayor.
Mr Trump also brushed off the fact that the Kremlin had hailed the new US national security strategy as being in line with its own views.
"I think he [Vladimir Putin] would like to see a weak Europe, and to be honest with you, he's getting that. That has nothing to do with me," he said.
Mr Trump also criticised Europe's role in resolving the war between Russia and Ukraine, saying: "They talk but they don't produce. And the war just keeps going on and on."
Mr Costa said that EU leaders are "very close" to striking a deal which would allow billions of euro in frozen Russian assets to help cover Ukraine's war needs over the next two years.
While Belgium has expressed concerns that it might carry legal and financial risks, which it could end up shouldering alone, Mr Costa has said that negotiators are "working hard" to deliver an agreement.
He said the European Commission was doing a "very good" job, and they were "fine tuning" a deal from a legal and technical perspective which would get over the line in a qualified majority vote.
EU leaders are due to take a decision on the matter next week in Brussels.
The Taoiseach said that the EU "must continue to increase the pressure" on Russia until it ends its "unjustifiable war" against Ukraine - and that included financial support.
President of the European Commission Ursula von der Leyen is seeking to supply €90bn of Ukraine’s budget requirements for 2026-27, estimated by the International Monetary Fund to be €137bn.
Moscow has denounced the reparations loan plan as "theft".
Additional reporting AFP
