(CNN) -- Bloggers in Myanmar, Iran and Syria work under some of the most repressive conditions in the world, facing tactics such as regulation, intimidation and even imprisonment, according to a report from the Committee to Protect Journalists.
The organization released a list of the "10 worst countries to be a blogger" to call attention to online oppression in connection with World Press Freedom Day, which was observed Sunday.
"Bloggers are at the vanguard of the information revolution, and their numbers are expanding rapidly," the group's executive director, Joel Simon, said in a report posted on the organization's Web site. "But governments are quickly learning how to turn technology against bloggers by censoring and filtering the Internet, restricting online access and mining personal data.
"When all else fails, the authorities simply jail a few bloggers to intimidate the rest of the online community into silence or self-censorship."
Myanmar -- also known as Burma -- is the worst place in the world to be a blogger, Simon's organization says. A military government restricts Web access and throws people into jail for posting critical material.
Burmese authorities have the capability to monitor e-mail and other communication methods and can block users from viewing the Web sites of political opposition parties, the organization says, citing research group OpenNet Initiative.
One Burmese blogger, Maung Thura, is serving a 59-year prison term for circulating video footage after Cyclone Nargis in 2008, the Committee to Protect Journalists says.
Number two on the list is Iran, whose authorities, the group says, regularly detain and harass bloggers who dare to criticize religious or political figures, the Islamic revolution or its symbols.
Third is the Syrian government, which the committee says detains bloggers for posting content deemed detrimental to "national unity."
Cuba is next on the "dishonor roll." Its government now holds in jail 21 writers who led online journalism in the early part of the decade, the organization says.
In Saudi Arabia an estimated 400,000 sites are blocked, the committee says, and in Vietnam the Orwellian-sounding Ministry of Information and Communication has created an agency tasked with monitoring the Internet.
Tunisia and Turkmenistan, nations where the Internet is heavily restricted, also find a place on the list.
So, too, does China, which maintains the most comprehensive online censorship program in the world, the organization says.
Chinese authorities, it says, rely on service providers to filter searches, block critical Web sites, delete objectionable content and monitor e-mail traffic. The committee said its research shows at least 24 online writers are in prison in the country.
Egypt rounds out the list at number 10. Local press freedom groups in the country documented the detention of more than 100 bloggers in 2008 alone, the organization says. Most reported mistreatment, and a number were tortured, it says.
"The governments on the list are trying to roll back the information revolution, and for now they are having success," Simon said in the report. "Freedom of expression groups, concerned governments, the online community, and technology companies need to come together to defend the rights of bloggers around the world."