The four people who died in a crash in Clonmel, Co Tipperary on Friday have been named as 24-year-old Luke McSweeney, his 18-year-old sister Grace, and Zoey Coffey and Nicole Murphy who were also both aged 18.
The four young people were on their way to a Leaving Cert results party, and the three girls had received their results just hours before.
The single-vehicle collision occurred at 7.30pm on Friday evening.
The victims have been removed from the scene and taken to Tipperary University Hospital, and postmortem examinations will take place in the coming days.
Taoiseach Leo Varadkar has said the nation is mourning following the tragic deaths.
Mr Varadkar said in a statement on Saturday: “It is with deep sadness that I learned of the tragic incident in Clonmel last night.
“Leaving Cert results night should mark the beginning of a world of opportunities for young people. It’s a milestone on the road from childhood to adulthood.
“For young lives, so full of possibility, to be cut short in this way is truly devastating and heartbreaking. The whole nation mourns them.
“My sincere condolences to the families and friends of those who have died and the wider community in Clonmel and Tipperary. The thoughts of the whole country are with them, their school and their community.
“I am assured that the school authorities and HSE will work together to put in place the necessary supports for their classmates and community. We must come together in times such as this.”
Superintendent Kieran Ruane, of Clonmel Garda Station, said: "I want to express my condolences and sympathies and the sympathies of every member of An Garda Síochána to the families of the four young people who lost their lives yesterday evening in this single vehicle road traffic collision at Hillview, Mountain Road, Clonmel.
"Luke McSweeney, 24 years, his sister Grace McSweeney accompanied by Nicole Murphy and Zoey Coffey, all aged 18 years were travelling in a car, at approximately 7.30pm, which struck a wall and tragically all four occupants lost their lives at the scene.
"An Garda Síochána supported by other emergency services including Clonmel Fire Brigade, HSE Paramedics, Tipperary University Hospital and Tipperary County Council initiated a major incident response.
"The scene at Hillview remains closed today and a technical and forensic examination is being carried out by An Garda Síochána Forensic Collision investigators.
"An incident room has been established at Clonmel Garda Station and an investigation has commenced under a Senior Investigating Officer. An Garda Síochána's focus is the preparation of an investigation file for the Coroner."
Family liaison officers have been appointed to each of the families to provide support "and the families will be kept updated as to the course of the investigation".
Tánaiste and Minister for Foreign Affairs Micheál Martin said: “Deeply saddened by the tragic, heartbreaking loss of four young lives in Clonmel.
“Our thoughts and prayers are with their families, friends, classmates, the first responders, and the entire community today.”
Father Michael Toomey, administrator in the parishes of Ardfinnan, Ballybacon & Grange, said the victims’ families had expressed gratitude to the emergency services who attended the scene.
“Sometimes no words seem adequate when a tragedy like what occurred in Clonmel tonight happens. No words can give comfort at this time,” he said on Facebook.
“My thoughts and prayers are with the families tonight who suffered a terrible loss in this terrible accident.
“Being with them this evening, I know they are so grateful to all of the emergency services and to everyone who helped them this evening.
“The local schools will be in touch tomorrow to help the entire community and to be there for everyone at this time.”
He added: “Of course, my thoughts and prayers are with the four young people who tragically lost their lives tonight, to their families, and their friends, on what should have been one of the happiest nights of their lives.
“Please, look out for one another in these days, and don’t be afraid to look for help and support in the coming days.” - Additional reporting from Press Association
