A neighbour who witnessed the horrific incident in Rossfield Estate was in tears as he expressed his heartbreak for the children who died.
The man, who asked not to be named, is a neighbour of the family. He told Dublin Live he heard a woman running down the road screaming.
"I heard a lady on the road screaming. I was in bed and had a look out and there was a woman running up and down the road saying 'please help me'
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"I went out onto the road and there were a lot of people and guards. The guards had weapons."
The man said the children were removed from the property and brought to hospital. He heard the next morning that all three children had died in the incident.
"This morning we found out that the poor children had passed away.
"I am just so devastated for the family in question and for the community. I just can't believe it. We're just in shock."
"My grandkids played with them. I was only talking to them two days ago. It's heartbreaking to find out they are no longer on this Earth
"No child deserve this."
Rossfield deaths: Twins, 8, and teenage girl, 18, die in violent incident in Tallaght
Paul who lives in the area was woken up by noise outside at the time of the incident.
He told Dublin Live: "At about half 12 I was lying in me bed and just heard a load of racket. It sounded like a robbed car. So I just pulled up me blinds and didn't see anything.
"That was it, took no more notice of it.
"Then this morning I got on me phone and I saw the breaking news and it said Rossfield Estate.
"I am shocked. Shocked to see this happen to three young kids. It's horrible for the area."
Local councillor Charlie O'Connor spoke to Dublin Live about the horrific incident.
He said: "I am just so shocked. I've been getting calls from early morning from residents asking me could I confirm the news.
"It's just so sad. There are no words you can use. The community here in Rossfield and in the general Tallaght area are deeply shocked.
"Obviously we have to sympathise with the family and make the point that the family have to be supported in every way.
"The Gardai on the scene last night were also deeply shocked as you can imagine."
"What else can I say. I can only sympathise with everyone who is going to be affected by this terrible event"
This morning gardai confirmed that a teenage girl, 18, and twins, a boy and a girl aged 8, died following a violent incident in Tallaght.
At around 12.30am on Sunday morning, gardai were alerted to an incident in Rossfield Estate. The teenager and two children were rushed to Crumlin Children's Hospital and were pronounced dead.
A male teenager, aged 14, was taken from the scene to Tallaght Hospital with non-life threatening injuries.
A male in his early 20s was arrested at the scene and detained at Tallaght Garda Station. He is currently being held under section 4 of the Criminal Justice Act 1984.
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