Russia's attack on Ukraine "is an outrageous and moral breach of the most fundamental principles of international law," Taoiseach Micheál Martin has said in a special televised address.
Martin said that Russian President Vladimir Putin's actions, the invasion of Ukraine, were "immoral and totally beyond comprehension."
Martin warned that sanctions on Russia "will hit hard and will be far reaching" and said Ireland stood with the people of Ukraine.
"Our thoughts are with the innocent people of Ukraine in this their most difficult hour. The use of brute force in a pursuit of a warped goal is an affront.
"There are repercussions for global security and the economy," Mr. Martin said.
Martin, according to an RTE report, said Putin "must be held accountable", as he warned that the EU is to adopt tougher sanctions "than ever before to hit Putin and his henchmen where it hurts."
"This Russian attack will cause untold hardship for Ukraine and Ireland will support them with humanitarian support," he added.
"We are in touch with Irish people in Ukraine, and our embassy staff are in a safe place. These sanctions have to be comprehensive and the most severe we have ever introduced and cannot be incremental."
The taoiseach was speaking ahead of his attendance at an emergency EU Council meeting.
"Young lives will be lost unnecessarily. It is unacceptable that in the 21st century we are witnessing
Martin said that the Ministers for Foreign Affairs and Justice would meet today to waive visas for Ukrainian family members to come to Ireland.
"The financial sector will be a key sector for sanctions, and trade and transport, but this will be discussed in greater detail this evening. No one country will be taking unilateral steps to deal with this issue. The U.S. and EU response is a rational response to protect lives."
According to the RTE report, all Irish citizens in Ukraine are being advised to shelter in a secure place.
Minister for Foreign Affairs Simon Coveney said Ireland stood in "complete solidarity" with Ukraine.
Speaking on RTÉ's Morning Ireland, Mr. Coveney described the Russian military operation as an "act of aggression" against an independent sovereign nation.
Russia is "lying to the world", he said.
"This is an illegal act of aggression by Russia. They are lying to themselves and they are lying to the world about the justification for it.
"This is, make no mistake, an act of aggression against Ukraine, an independent, sovereign country that is being attacked by an aggressive neighbor, but it is also in many ways an attack on the kind of Europe we have built together, collectively since World War Two.
"There have been continuous efforts to reach out to President Putin and (Foreign Minister) Minister Lavrov in terms of trying to provide a basis for an alternative to war and Russia has decided to ignore all that and proceed with what seems to have been planned for quite some time."
"The EU and its partners need to respond. We are not going to go to war with Russia militarily, but certainly I think the response in terms of sanctions will be very direct and very hard hitting," Coveney said.
"We are seeing a language that we simply have not seen in many, many decades in Europe of aggression and of potential brutality."
Earlier, coverney had tweeted: "Russia has launched a full-scale invasion of Ukraine. God help them."
Ireland's diplomatic team in Kyiv has moved to a safe place, Mr. Coveney said, and that work is under way with other colleagues from EU member states to "ensure their safety."
Ireland's ambassador to Ukraine is Thérèse Healy.
