TOKYO (Kyodo) -- MUFG Bank has fired an employee for allegedly stealing assets worth between 1 billion ($6 million) and 2 billion yen from safe deposit boxes of some 60 customers in Tokyo, the Japanese megabank said.

The worker was dismissed on Nov. 14 after admitting to stealing the assets at two branches from April 2020 to October this year. The bank is investigating the theft and consulting with police, it said Friday.

The bank said the thefts occurred at the Nerima and Tamagawa branches and the exact value of the items stolen is still being investigated.

The incident came to light on Oct. 31 after the bank received an inquiry from a client, it said. The bank has confirmed there were no similar incidents at other branches after conducting an emergency assessment.

"The former employee was responsible for managing the safe deposit boxes and took advantage of this position to open customers' safes without permission and steal their assets," MUFG Bank said in a statement.

The bank failed to prevent the incident despite having strict rules governing safe deposit box management and a system under which periodic checks are conducted by a third party, the bank added.

The bank said it has already contacted the customers affected and will swiftly compensate them. It has not disclosed details of the former worker.

The incident comes in the wake of another in which a former employee at major Japanese financial firm Nomura Securities Co. was indicted earlier this month on suspicion of robbery, attempted murder and arson.

Yusei Kajiwara is alleged to have stolen some 18 million yen in cash from an elderly couple after rendering the woman unconscious with a sleeping drug and then setting their house on fire on July 28, according to the indictment. The couple, who were Nomura customers, escaped unscathed, investigative sources said.