Gardai are investigating a threatening email sent to a number of schools.
Some schools in Co Clare received a message on Tuesday, which officers said they are assessing.
In a statement, gardai said that, following initial assessment, they are “satisfied that the security threat is not credible and there is no ongoing risk to the public”.
A number of schools across the county remain closed until they receive further instructions.
The sender of the email threatened to carry out “the most prolific attack in Irish history”.
They said they would be armed with “multiple firearms” and that they had placed items around every school included in the email, and would be “successful in my plan”.
The email also stated that they had sent a copy of their “manifesto” to the local newspaper.
Gardai said in a statement: “Gardai are engaging with the affected educational establishments with regard to this incident.
“Inquiries are ongoing. No further information is available at this time.”
We need your consent to load this Social Media content. We use a number of different Social Media outlets to manage extra content that can set cookies on your device and collect data about your activity.
Sinn Fein TD Donna McGettigan said she understood that all schools in the Co Clare area have been affected.
“The schools have been very reactive and took immediate precautionary measures as soon as they could,” the Clare TD told the PA news agency.
“Most of the schools closed before the students arrived but there were a few where the pupils were already inside, so their parents had to go back and take them home. Many of the children were upset about this.
“This has caused a lot of fear and anxiety among children and their parents. A lot of people have been contacting me about this.
“Gardai now say that the threat is not credible so that will help allay parents’ concerns.
“Well done to all the schools who took precautionary measures, and fair play to gardai who were on the ball straight away.”