The Romanian unit of France's Societe Generale, BRD, said it thwarted an attempt by a clerk to steal 8 million lei ($3.19 million) this week, managing to block a large part of the transfer.
"The unauthorised operation of two cash transfers worth a total of 8 million lei by a clerk of the BRD Craiova Group was detected by the internal control systems of the bank ... in less than two hours," the bank said in a statement sent to Reuters.
The incident occurred at the BRD's branch in the city of Craiova.
Local media quoted unnamed sources saying the clerk illegally used the password of a local branch director.
"The members of the criminal network were arrested and their assets were seized. The amount yet to be recovered is the equivalent of 350,000 euros ($510,000)," the statement said.
On Jan. 24, SocGen revealed 4.9 billion euros of losses which it said were caused by rogue trades conducted by Jerome Kerviel, a 31-year old trader at the bank.
Kerviel has been placed under formal investigation for breach of trust, computer abuse and falsification and freed under judicial supervision, which resembles bail.