The western Japan city of Amagasaki said Thursday it has lost a USB flash drive containing personal information on all of its roughly 460,000 residents.

The lost data included residents' names, addresses, dates of birth and the bank account numbers of welfare-receiving households, among other things. There is no evidence of data being leaked so far, according to the city in Hyogo Prefecture.

Aerial photo taken from a Kyodo News helicopter on June 23, 2022, shows the city hall of Amagasaki in Hyogo Prefecture. (Kyodo)

An employee of a company commissioned to assist the city's rollout of COVID-19 relief funds lost a bag that had the flash drive inside after dining and drinking at a restaurant Tuesday, the city said.

The employee reported to police Wednesday. The data were encrypted and protected with a password, according to the city.

"We will thoroughly ensure security management when handling electronic data," the city said in a statement. "We will work to regain our residents' trust by heightening awareness of the importance of protecting personal information."