A large volume of English-language junk emails marketing impotence drugs has been circulating in Japan, the Internal Affairs and Communications Ministry, quoted by a local paper, said.
The Yomiuri Shimbun said this was the first confirmed instance of English-language junk emails sent to mobile phones, according to the agency.
The agency further reported that Japan's mobile carriers had launched anti-spam efforts following the discovery of the spam.
Mobile phone carrier Softbank had introduced a system that enabled users to block unsolicited emails and was urging its mobile phone users to change the settings on their mobile phones to use the system, the report said.
According to Softbank, there are several versions of English-language emails touting male impotence drugs. If a user accesses the address on the email, a page is displayed listing the types of drugs and prices.
NTT DoCoMo and KDDI, which ran the au and Tu-ka services, respectively, were also examining measures to counter English-language junk emails, the paper said.