Detectives are investigating a cyber attack on some of the island of Ireland's most popular supermarket chains.
Criminals attempted to get credit and debit card details of shoppers who use stores owned by grocery company Musgrave.
Musgrave said the attack targeted its SuperValu, Centra, Daybreak and Mace stores. It said malicious software had been used to try to steal the information of customers.
The malware also tried to take the expiry date of the cards but did not try to access cardholders' names, PINs or CCV numbers, the company said.
Musgrave said it does not store card data.
The details of customers in both the Republic and Northern Ireland were understood to have been targeted in the attack.
Musgrave operates the SuperValu and Centra brand networks on both sides of the border, while in the Republic it runs Daybreak stores and in Northern Ireland, Mace.
The incident has been reported to gardai and Ireland's Data Protection Commissioner. The Police Service of Northern Ireland has offered assistance to the Garda-led probe.
"While there is no evidence that any data has been stolen at this point, Musgrave is advising any concerned shoppers to review activity on their statements as a precautionary measure," the company said in a statement.
Musgrave also said it has "cyber breach response experts" and they have installed advanced technical fixes to combat the attempted breach.
The company said it would continue to actively manage and monitor the situation.
"The protection of information is an absolute priority for Musgrave, with a range of security solutions including threat-monitoring, anti-virus software, firewall and penetration testing deployed," Musgrave said.
"The company aims to ensure that security standards are maintained at the highest levels and apologises to its customers for this issue."
SuperValu has more than a fifth of the supermarket share in Ireland.
Dublin Information Sec 2017, Ireland’s cyber security conference, addresses the critically important issues that threaten businesses in the information age. For more on INM’s Dublin InfoSec 2017 conference, go to: independent.ie/infosec