Gardaí have yet to make any arrests in connection with an assault on a teenager in Navan, Co Meath.
Footage of the Monday afternoon attack has been widely shared on social media, with speculation that it was motivated by homophobia.
A juvenile attended Our Lady of Lourdes Hospital in Drogheda following the incident, where he received treatment for serious facial injuries.
The victim of the assault and the alleged perpetrators are understood to be students in Navan.
The taoiseach described the attack as "horrifying".
"It looks to me like somebody was targeted because they're different and they were humiliated and physically assaulted," Leo Varadkar said
He said he wanted to "send out his solidarity to the young person who was harmed and injured".
"I really want to say to them that life does get better. It's very sad that people experience violence and bullying in school but life does get better and not to give up," the Fine Gael leader said.
Mr Varadkar expressed sadness "how in this day and age we still see this kind of bullying and violence happening in our schools".
He urged anyone with information to cooperate with the Garda investigation.
Aontú leader and Meath West TD Peadar Tóibín condemned the incident.
"Footage circulating online of a vicious and horrific attack on a school child in Navan is deeply concerning, the attack appears to have taken place in view of two schools," he said.
"The gardaí must thoroughly investigate this matter – no child should feel unsafe in school, at lunch, or after school."
A statement from An Garda Síochána said the incident was being investigated.
"An Garda Síochána is aware of a video circulating on social media of this incident and out of respect for the victim in this case we would request that people refrain from sharing this video," the statement said.
