Japanese mobile phone operator Softbank says it is experiencing a major disruption to its phone and data communication services.
The company says the problem started at 1:39 PM, Japan time.
The issue has also been affecting Softbank Group company Y! Mobile, as well as some other telecom companies that use Softbank's networks, including Line Mobile, b-mobile, mineo, nuro mobile and H.I.S. Mobile.
The operator says it is still investigating the cause and the magnitude of the issue. It has apologized to users for the inconvenience.
The Tokyo Fire Department posted a message on Twitter to request that in the case of an emergency, people use landline services or networks other than Softbank's.