U.K. Royal Mail says overseas postal services unavailable after 'cyber-incident'

Overseas service with the U.K. Royal Mail are temporarily suspended after a "cyber-incident," the British agency said Wednesday. 

The mail service held back from calling the incident an "attack," indicating it had not yet determined whether the problems were inadvertent or the work of an antagonist of unknown origin. 

"We immediately launched an investigation into the [cyber] incident and we are working with external experts," Royal Mail told media. 

Domestic service is reported to be unaffected.