Hackers possibly have stolen 90,000 customers personal Data from two Canadian banks Bank of Montreal (BMO.TO) and Canadian Imperial Bank of Commerce (CM.TO).

The banks warned customers on Monday that they have been targeted by hackers and thousands of records customers personal information has been stolen.

BMO.TO was contacted by hackers on Sunday and they claimed to have personal data of a number of clients. Bank of Montreal spokesman Paul Gammal said “they believe had stolen data on up to 50,000 of the bank’s customers.”

CIBC-owned Simplii Financial warned by hackers claiming to have personal data of 40,000 customers, and after an initial investigation, CIBC was the first one to warn about the incident.

The fraudsters had threatened to make the data public, the spokesman said, adding that the bank was working with the authorities and conducting a thorough investigation. Reuters reported.

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Simplii not yet confirmed the data breach, the investigation still in progress and it continues to notify affected clients “through all channels” if it is determined they have been compromised.

Cyber crooks claim to hit two big Canadian banks https://t.co/RzyIRQVYix pic.twitter.com/1b81oHRiMr

— Reuters (@Reuters) May 28, 2018

We feel that it is important to inform clients so that they can also take additional steps to safeguard their information Michael Martin, senior vice-president of Simplii Financial said.

We took steps immediately when the incident occurred and we are confident that exposures identified related to customer data have been closed off. We have notified and are working with relevant authorities as we continue to assess the situation,” BMO said in a statement.

Other major Canadian banks were not affected by the incident, BMO said the hackers appear to be operating outside of Canada.

“Someone claiming to have the stolen data sent a letter to media outlets across Canada later in the day. The email ended with a sample of the information in question: the names, dates of birth, SIN and account balances of an Ontario man and a woman living in B.C.” reported CBC.

CIBC said, “if any of the clients is a victim of fraud because of this issue, we will return 100 percent of the money lost from the affected bank account.”