A Ukrainian member of parliament says Russian soldiers are shooting at women and children who are trying to flee the conflict.
Kira Rudyk was speaking amid international condemnation of a Russian airstrike on a maternity hospital in Mariupol.
Taoiseach Micheál Martin criticised the 'indiscriminate cruelty of Putin's invasion' of Ukraine.
"This war on civilians must end", Mr Martin said on Wednesday.
Ukraine's President Volodymyr Zelenskyy tweeted that children were "under the wreckage", calling the strike an "atrocity".
"How much longer will the world be an accomplice ignoring terror?", he asked.
Mariupol. Direct strike of Russian troops at the maternity hospital. People, children are under the wreckage. Atrocity! How much longer will the world be an accomplice ignoring terror? Close the sky right now! Stop the killings! You have power but you seem to be losing humanity. pic.twitter.com/FoaNdbKH5k
— Володимир Зеленський (@ZelenskyyUa) March 9, 2022
It comes as European Union leaders are meeting for a two-day informal summit in France to discuss the invasion.
Mr Martin aims to use the summit to discuss the implications of the refugee crisis and rapidly spiraling fuel costs.
EU diplomats have agreed in principle a third round of sanctions against Russia, which will focus on asset seizures and travel bans for oligarchs along with cryptocurrency assets held in Europe.
Deputy Rudyk told The Hard Shoulder the world now sees Russian President Vladimir Putin as he is.
"For the city of Mariupol, that has been under siege, for three consecutive days Putin promised that he will let the humanitarian convoy out.
"And three times in a row when these women and children, who were melting the snow for water, were trying to get out Russia soldiers were shooting at them.
"[They] were firing their guns so they had to come back.
"And if Putin cannot keep his word in this fairly minor thing, why would the world expect him to be ready for diplomatic negotiations?
"So we know not to trust Putin, but now the whole world sees he cannot be trusted."
She says the bombing of the maternity hospital is "extremely beyond anything - this cannot be happening in the 21st century in a city at the centre of Europe.
"It just cannot be happening, and what I feel is complete rage".
'Radiation doesn't care about your passport'
She also criticed NATO's refusal to implement a no-fly zone over Ukraine, saying that any potential nuclear incident will not stop at a NATO border.
"The NATO countries refuse to support Ukraine and give us the no-fly zone - they say we're afraid that there will be a third World War started.
"So I have a question then: Putin bombarding the nuclear plants - how does that sound to you?
"Do we all think that radiation will be picking up who is [a] NATO country and who is not?
"As a person who lived near Chernobyl, I can tell you right away: radiation doesn't care about your passport".
And she believes nothing suggests President Putin will stop at Ukraine.
"We are not asking [you] to fight for us - though thank you for all 16,000 people who came from all over the world and are fighting for us.
"But we are saying we are fighting our war ourselves, help us - because we are protecting so this plague will not come on to other countries.
"Look at the countries that Putin already put his forces at - Belarus, Kazakhstan, Georgia - why do we think that he will stop?
"What are the facts that make the world think that Putin can be contained?"