TOKYO (Kyodo) -- Japanese megabank MUFG Bank said Thursday that its internet banking service has been unstable, indicating that it may have been under a cyberattack.

The glitch, which occurred from 2:47 p.m., originated from "massive influx of data," the main banking unit of Mitsubishi UFJ Financial Group Inc. said. There was no leakage of customer information, nor was any damage caused by computer viruses.

Customers could experience delays in internet transactions such as difficulties of logging into the system, the bank said.

Also on Thursday, Japan Airlines' network suffered a cyberattack, which delayed flights at the start of the New Year holiday season. The system was restored later in the day.