Under the backing of the U.N. Educational, Scientific and Cultural Organization, the group urged Internet users to protest against the nine countries where some 63 cyberdissidents are jailed.

"China continues to be the world's biggest prison for online journalists and bloggers," the group says on its Web site, www.rsf.org.

Other countries listed as cyberprisons are Myanmar, North Korea, Cuba, Egypt, Eritrea, Tunisia, Turkmenistan and Vietnam.

In addition to celebrating free expression day, the group is having a "24-hour online demo against Internet censorship."

Internet users are invited to access the group's Web site where they will be able to create an avatar, choose a message for their banner and take part in one of nine cyberdemonstrations against "Internet enemies."