Up to seven primary schools across Northern Ireland have been evacuated by the PSNI after threats were made.
The PSNI is not releasing details of which schools at this stage but is taking the threats seriously.
The first alert came at Bloomfield Primary School in Bangor.
It was later confirmed that a primary school in Larne had also been evacuated.
Others in Coleraine, Castlereagh and Newtownards have also been reported to have received malicious communications.
The calls come after similar incidents in the West Country in England yesterday (Monday).
Police say they are liaising with colleagues on the mainland.
Chief Superintendent Simon Walls said: “We are investigating a series of malicious communications to schools across Northern Ireland today.
“At this stage there is no information to suggest the incidents are terrorist-related, however enquiries continue to establish the facts. We will liaise with other UK Police services who have received similar calls, to investigate who is responsible and whether these incidents are linked.
“Anyone with information should contact police on the non-emergency number 101 or call Crimestoppers anonymously on 0800 555 111.”
We are investigating a series of malicious communications to schools across NI today. Anyone with info should contact us on 101. #PSNI
— PSNI Armagh (@PSNIArmagh) 24 May 2016