The bombing attack in Manchester was a "barbaric attack on children and an assault on civilisation", Ceann Comhairle Seán Ó Fearghaíl told the Dáil.
A minute’s silence was observed in tribute to the 22 people killed and the 59 seriously injured in the suicide bomb attack.
Leading tributes to the victims of the attack, Mr Ó Fearghaíl expressed his “deep revulsion and sadness”.
Mr Ó Fearghaíl said the Dáil extended condolences to colleagues in Westminster and he had contacted speaker John Bercow. "Tonight we in Ireland will hold our own children even closer."
President Michael D Higgins described the murder of so many young people in Manchester last night as a "cowardly attack on innocent citizens" which "will have appalled all those who care for democracy, freedom and the right to live and enjoy the public space".
Speaking in the Dáil, Taoiseach Enda Kenny said the "atrocity is made all the more appalling by the targeting of young people".
Mr Kenny was due to speak to British prime minister Theresa May by telephone Tuesday morning but he said it had been rescheduled for the evening.
He said for children and youngsters going to such concerts the “excitement goes on for months beforehand. It’s a huge adventure.
“You have brought your children to a concert venue. You leave them outside as they go in to an adventure. To think some of them never came back.”
He said the security level in Ireland “remains at moderate”, which meant an attack was “possible but not likely”. He added: “We do not have any evidence of it being beyond the moderate stage.”
Tánaiste Frances Fitzgerald said there was “close liaison between An Garda Síochána and their UK counterparts about last night’s dreadful events and this is taking place against the background of intensive ongoing co-operation with international security agencies”.
While there was no specific information about a threat to Ireland, “last night’s attack is a reminder that no one can be considered immune from those whose hatred of our values drives such evil acts”.
Hatred and cowardice
Fianna Fáil leader Micheál Martin expressed his sympathies and said "our thoughts and prayers are with the families. It was a barbaric attack on innocents, on young children enjoying themselves."
Sinn Féin leader Gerry Adams expressed his party's "sincerest and heartfelt solidarity". He said it was a "harrowing attack on people going about their evening, having a big night out".
Labour's Sean Sherlock said it was "probably no accident that this attack targeted mostly women and young girls and happened during a general election".
Solidarity People Before Profit TD Richard Boyd Barrett said "any attack that deliberately targets children and families who are out just having fun cannot be other than barbaric and condemned".
Trauma
Independents4Change TD Clare Daly, who highlighted the "pain, panic and heartache" in Manchester, said there were so many parents in Ireland who dropped their children to the Ariana Grande concert in Dublin at the weekend.
Becoming emotional, Ms Daly said “it brings the trauma of that home”.
Social Democrats TD Catherine Murphy said it was not easy "to comprehend or visualise the mindset of those who carried out this outrage" and such atrocities "leave a deep scar on families and communities".
Green Party leader Eamon Ryan said "our hearts go out to those families and their shattered lives".
