The Taoiseach says Russian President Vladimir Putin is trying to force Ukrainians to leave their country by bombing residential areas.
Micheál Martin was speaking after he met Ukrainian Prime Minister Denys Shmyhal for over an hour at Shannon Airport earlier.
The two leaders discussed the ongoing war and humanitarian crisis in Ukraine.
Mr Martin says he was given a first-hand account of events in Ukraine.
"Very clearly the strategy of the Putin regime is not just in terms of killing people, but also causing huge international instability around energy and around food.
"So for example, the largest grain silos in Ukraine have all been levelled.
"So there's a very clear, strategic objective there to create a food crisis on top of the energy crisis that has been created - as well as raging an immoral and unjust war on Ukraine itself."
Met the Ukrainian PM @Denys_Shmyhal in Shannon today.
He gave me first hand account of shocking and horrific campaign of terror on civilians in #Ukraine by Putin’s regime.
I assured him of Ireland’s support for strongest sanctions against Russia and for Ukraine’s EU membership. pic.twitter.com/EOPTteCuCb
— Micheál Martin (@MichealMartinTD) April 20, 2022
The Taoiseach says Europe will face up to the migration challenges.
"The situation is very challenging indeed, but we have to do everything we possibly can on all fronts to be of assistance and to help the people fleeing Ukraine.
"In our discussions with the Prime Minister - they're very clear that there is a deliberate strategy on behalf of Putin to literally bomb people out of Ukraine.
"To create so much terror, that people will flee.
"So for him the challenges for Europe in terms of the number of displaced people leaving, is something he wants to create.
"And I think we've got to be equally robust, in the sense of the entire European continent, in response".