Taoiseach Micheál Martin has criticised the 'indiscriminate cruelty of Putin's invasion' of Ukraine.
He was reacting to reports that children have been buried under rubble after a Russian airstrike hit a hospital in Mariupol.
Ukraine's President Volodymyr Zelenskyy tweeted that children were "under the wreckage", calling the strike an "atrocity".
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
Mariupol's City Council said the maternity and children's hospital had been destroyed, adding that it did not know any casualty figures but that "the destruction is colossal".
The governor of Donetsk region said 17 people, including women in labour, were wounded in the airstrike.
The governor added that the airstrike happened during an agreed ceasefire period to allow civilians to safely escape.
And video footage from the hospital shows bloodied pregnant women being brought out on stretchers.
"This war on civilians must end", the Taoiseach says.
With multiple reports of a missile strike destroying maternity & children’s hospital in #Mariupol, despite ceasefire agreement, the indiscriminate cruelty of Putin’s invasion is crystal clear.
This war on civilians must end.
— Micheál Martin (@MichealMartinTD) March 9, 2022
In the grounds there is a huge crater, estimated to be about 20ft deep and 30ft wide.
It comes as the UN Human Rights office has verified 1,424 civilian casualties since Russia invaded two weeks ago - with 516 people killed and 908 injured.
The southern port city of Mariupol is surrounded by Russian troops and has been subject to heavy shelling for days, leaving thousands of people without food, water and electricity.
The Ukrainian government said 1,170 civilians have been killed in Mariupol since Russia began its invasion, citing the city's deputy mayor.
People in the city have been forced to get water from melting snow, while some bodies lay in the street from intense bombardment.
On Tuesday a six-year-old girl named Tanya died alone from dehydration in the ruins of her home in the city after her mother was killed in shelling by Russian forces, Ukrainian authorities said.
New ceasefires were announced on Wednesday morning to allow thousands of civilians to escape from towns around Kyiv as well as the southern cities of Mariupol, Enerhodar and Volnovakha, Izyum in the east and Sumy in the northeast.
Previous attempts to establish safe evacuation corridors largely failed because of what the Ukrainians said were Russian attacks.
But Russian President Vladimir Putin, in a telephone call with Germany's Chancellor Olaf Scholz, accused militant Ukrainian nationalists of hampering the evacuations.