The military junta sharply restricts press freedom. Legal restrictions on freedom of speech include a ban on statements that "undermine national security" and a stringent licensing system. Other decrees criminalize the possession and use of unregistered telephones, fax machines, computers and modems, and software. The government owns all broadcast media and daily newspapers and exercises tight control over a growing number of private weekly and monthly publications. It subjects private periodicals to prepublication censorship, and limits coverage to a small range of permissible topics. During the year, a number of publications were banned when they failed to comply with official regulations. In May, the junta also banned Thai advertising in the media, a move that threatened the financial viability of privately owned publications. Self-censorship is common. According to the Committee to Protect Journalists, international correspondents are generally not allowed to establish a base in Burma, and foreign reporters, who must apply for special visas to enter the country, are subject to intense scrutiny. In October, dozens of dissidents were arrested and detained for the possession of banned newspapers. Although several journalists were released from prison in 2002, more than a dozen remain incarcerated.