Japanese electronics giant Hitachi Ltd.'s in-house computer system has been destabilized, with some email messages and attachments being blocked, company officials said the same day.

Although the scale and cause of the problem are still under investigation, Hitachi believes that its system was attacked by global ransomware that reached epidemic proportions on Friday, according to the officials.

A computer used at a branch office of East Japan Railway Co. or JR East, was infected with a virus on Friday that is apparently linked to the global cyberattacks.

According to JR East public relations officials, the infection has not affected train operations or other services as the computer, used mainly to browse the Internet, is not connected to in-house information networks.

The train operator is currently investigating the situation, they said.

There have been 200,000 cases of infections over at least 150 countries as a result of the recent ransomware attacks, according to overseas media reports.

Nissan Motor Co.'s Sunderland plant in Britain stopped production on Friday night due to an attack on its computer systems.

Major Japanese antivirus software maker Trend Micro Inc. unearthed nine infections caused by the ransomware attacks among 175 inquires made between Friday and 4 p.m. on Monday (7 a.m. GMT).

Japan's National Police Agency said that seven domestic damage cases had been confirmed as of 5 p.m. the same day.

Of the seven, one was at a hospital in Ibaraki Prefecture and another at a company in Gunma Prefecture, both in eastern Japan. The other five cases involved the computers of residents of Tokyo, the central prefecture of Shiga, western prefectures of Okayama and Kagawa and the southwestern prefecture of Fukuoka.

The city of Kawasaki, Kanagawa Prefecture, south of Tokyo, said a computer used at its water bureau was infected with a ransom-demanding virus but the municipal government's administrative information system remained unaffected. (Jiji Press)