Three young children and a woman have been injured in what Ireland’s Justice Minister Helen McEntee has described as an “appalling attack” in Dublin city centre.
A man has also been taken to hospital following the incident on Parnell Square East in the north inner-city on Thursday afternoon.
Taoiseach Leo Varadkar said a suspect had been detained.
One of the children, a girl, and a woman sustained serious injuries in the incident.
A man and the two other children sustained less serious injuries, the Garda said.
A spokesman said the force had been in contact with the parents of the injured children.
Gardai said they were following a definite line of inquiry and were not looking for anyone else in connection with the incident at this time.
Witnesses at the scene reported seeing victims with what appeared to be stab wounds.
The scene of the incident is close to Irish language-medium primary school Gaelscoil Cholaiste Mhuire.
Siobhan Kearney said she witnessed what she believes was a man attacking children.
She described what she saw as “absolutely bedlam”.
Ms Kearney told RTE she watched people disarm a man who she said had a knife.
“I looked across the road and I see the man and the stabbing motion with a load of children so I flew across the road,” she said.
“The man was after stabbing two children as far as I could make out, and we got the children up to the left with the women that were there, and the teachers I presume.
“People were trying to attack the man so me and an American lady, we formed a ring around the man, and then about three minutes later the ambulance came for the children and then another ambulance and fire officers came for the man on the ground.”
Ms McEntee said she was “deeply shocked” by the “appalling attack on three innocent children and a woman”.
She said: “All our thoughts are with those injured, especially with the children, their parents and families, during this extremely difficult period.
“I have been briefed by the Garda Commissioner (Drew Harris) and will remain in close contact with him and senior gardai.
“It is my understanding that gardai are following a definite line of inquiry and are not looking for any other person at this time.
“This attack has shocked us all, and I have no doubt that the person responsible will be brought to justice.”
She added: “However, my thoughts now are with the innocent children and the woman who have been attacked, their families, and those who are caring for them at this time.”
We are all shocked by the incident which has taken place in Parnell Square— Leo Varadkar
Irish premier Mr Varadkar said: “We are all shocked by the incident which has taken place in Parnell Square.
“A number of people have been injured, some of them children.
“Our thoughts and our prayers go out to them and their families.
“I have been in contact with the Minister for Justice who is keeping me updated.”
He added: The facts in this matter are still emerging.
“The emergency services responded very quickly and were on site within minutes. I thank them for that.
“Gardai have detained a suspect and are following a definite line of inquiry.”
Irish Minister for Public Expenditure Paschal Donohoe said his thoughts and prayers are with the victims.
He said: “I am aware of an extremely serious incident that has taken place at Parnell Square in my constituency of Dublin Central.
“My thought and prayers are with the victims of this very serious incident, and their families.
“Anyone with information is being asked to contact Store Street police station.”
Sinn Fein leader Mary Lou McDonald said the incident in Dublin city centre had caused “shock and horror”.
In a social media post, Ms McDonald said: “Violent attack at Gael Cholaiste Mhuire Parnell Square has sent shock and horror throughout the community.
“My heart goes out to all the hurt and injured, the parents, teachers but especially the children who have been so traumatised.
“This is beyond words.”
