An American computer security expert sued the government Monday for 30 million yen, claiming the communications ministry had suppressed his freedom of speech.

The petition filed by Ejovi Nuwere at the Tokyo District Court says the Internal Affairs and Communications Ministry earlier this month pressured the organizers of an international security conference to cancel his lecture on flaws in the government's online citizen registry network.

The lecture was designed to highlight problems with the system so as to improve security, Nuwere, 24, said after filing the lawsuit, adding that he cannot overlook the ministry's efforts to censor him.

The lecture was to be based on Nuwere's security audit last year on the Juki Net system on behalf of Nagano Prefecture.

The seminar, which was supported by the ministry, was held Nov. 12 in Tokyo.

Ahead of the seminar, the ministry had raised concerns about Nuwere's presentation and shortly before he was to speak demanded that he remove the slide outlining his conclusions. At that point, Nuwere canceled his lecture, according to the petition.

Nuwere conducted the experiment on Juki Net for the Nagano Prefectural Government and said private information in the system can be altered.

Under Juki Net, launched in August 2002, each resident is identified by an individual code. Personal details, including name, address, date of birth and sex, are registered by local municipalities, via prefectural governments, in a database run by the central government.