An investigation has been launched following an attempt to hack into the Garda Síochána (Irish Police) computer system.
The incident forced the shut down of a number of internal systems last week according to Irish broadcaster, RTÉ.
It is not clear who was behind the attack.
The force’s IT security team had not previously seen the type of threat involved.
The garda computer systems contain highly sensitive data ranging from open criminal investigation files to data relating to members of the public and staff.
It is understood no data was compromised in the attack but garda management is treating it very seriously.
The Computer Crime Unit at the Garda Bureau of Fraud Investigation is investigating, gardaí said in a statement this afternoon.