French regional bank Credit Mutuel Arkea said Wednesday it had been the victim of a cyberattack that allowed fraudulent transactions, which reports claim amounted to $133 million (118 million euros).
The bank, an arm of French financial services giant Credit Mutuel in western France, said the attack was "under control" and there would be "no financial consequence" for its clients.
The institution did not give details on how the attack was carried out or who could be behind it, nor did it confirm the amount lost -- which was first publicised by independent investigator ZachXBT and widely picked up in media reports.
Companies across Europe are on heightened alert after a spate of suspected hacks of supermarket fridges and freezers in recent days caused chaos.
"Our teams mobilised immediately after detecting the attack and, as a precautionary measure, decided to temporarily suspend certain transactions in order to secure operations and prevent any further fraudulent activity," Arkea said.
"These operations will resume shortly, under optimal security conditions, once the final checks and security measures have been completed."
ZachXBT, an independent investigator who specialises in tracking funds on the blockchain --the system that underpins cryptocurrency transactions -- revealed the fraud on his social media accounts earlier in the week.
The anonymous online sleuth said the stolen funds had been routed through multiple accounts opened on crypto exchange platforms.