An investigation is under way after a number of schools did not open in Co Carlow this morning.
The Department of Education and Youth confirmed that the closures followed "concerning communications" the schools received.
An email was sent to several primary schools in the county with up to 10 schools making the decision to close.
The principal of St Joseph's National School in Carlow town, Fergal Browne, said that he believes the threat was a hoax, but it was "very upsetting" for children and parents.
Mr Browne, who is also a local Fine Gael councillor, said that a "generic email" was sent from an unknown account threatening that there would be a shooting.
He told RTÉ News that gardaí had responded appropriately to the threat and he wanted to compliment them for their support this morning.
Mr Browne said he decided to keep St Joseph's NS open after liaising with gardaí.
He said: "We want to reassure all parents and guardians. These things happen, unfortunately. It is very upsetting for school staff and parents. We are being extra vigilant today and are liaising with gardaí at all times."
A Department of Education spokesperson said: "The safety and wellbeing of children is the department's first priority and An Garda Síochána is in direct contact with the affected schools to assess the situation and provide support to them.
"The department will continue to work closely with An Garda Síochána and affected schools throughout the day," the spokesperson added.
Gardaí said they are assessing the credibility of the contents of the email and are in contact with the schools affected.
