A 14-year-old pupil allegedly pulled a knife on another boy and held it to his throat during a row in a south Dublin secondary school.
The incident caused deep concern among parents of children attending the school.
One mother told Independent.ie her child and others have been “very nervous” since.
It is understood the incident happened at around lunchtime on Monday, October 1 when an argument between two pupils broke out “over the code for a door”.
One boy has been suspended, but is not thought to have been expelled.
The principal of the school did not return requests for comment.
Gardai from Dundrum are investigating the incident, though it is understood there will be no criminal prosecutions.
While the second-year pupil was questioned by officers, he was not arrested.
“Gardai attended a school in south Dublin following a report of an incident,” a garda spokesperson said.
“The matter will be dealt with by the school.”
No one was injured and “no criminal offence has been disclosed”.
“This issue will be primarily dealt with by the school, but Garda Juvenile Liaison officers are also involved and are dealing with it,” a source said.
One parent told Independent.ie: “A second-year student upended a classroom and held another student up against a wall with a knife to his throat,” a parent said.
“Students were terrified and went running and screaming.
“This student was suspended and is now back in class.
“Parents are talking about taking their kids out for their own safety.”
The school’s principal and deputy principal wrote to parents and guardians immediately after the incident, informing them that a “thorough investigation” had been launched.
“The student will not be in class while the investigation is being carried out,” they added.
“Please be assured that the safety and well-being of all our students and staff is our primary concern.”
In follow-up correspondence sent last Friday, the principal thanked parents for their support.
“All relevant authorities have been consulted and we are following the school’s policies and procedures which are based on best national practice,” she said.
“I understand how unsettling and frightening this must be for you as parents and for your children.
“Last Tuesday I addressed the students at assembly and assured them that their safety is the primary concern of all the staff and the board of management and that they should speak to a member of staff if they are concerned, worried or upset.”
She offered the services of a guidance counsellor, year head and tutor if needed.
However, one parent claimed they could not get “a direct response” from the school when they asked questions about the incident, and the matter has caused “a lot of unrest”.