KDDI Corp. said Monday its "au" mobile phone services experienced technical difficulties across Japan, causing disruptions to calls and internet connections, but it has resolved the problems.

The service disruption, which began at 7:18 a.m., initially affected 31 prefectures in western Japan, including Osaka, Kyoto, and Fukuoka, before extending across the country.

The services returned to normal around 10:11 a.m., according to KDDI, one of Japan's three major telecommunications carriers.

The company said that some services, particularly data communication, were impacted nationwide. The cause of the outage remains under investigation.

==Kyodo

© Kyodo News International, Inc., source Newswire