Ten countries in the world ruled by dictators have imposed the most drastic censorship by shutting out international media and cracking down on journalists at home, the Committee to Protect Journalists (CPJ) said in a report released on Wednesday.

Of the 10, Syria, Iran and North Korea stand out for their vast restrictions on the flow of information and thus create "enormous implications for geopolitical and nuclear stability," the New York-based CPJ said in its first report since 2006, issued to coincide with World Press Freedom Day on Thursday.

At the top of the list is Eritrea, followed by order of importance by North Korea, Syria, Iran, Equatorial Guinea, Uzbekistan, Myanmar, Saudi Arabia, Cuba and Belarus.

"The 10 most restricted countries employ a wide range of censorship techniques, from the sophisticated blocking of websites and satellite broadcasts by Iran to the oppressive regulatory systems of Saudi Arabia and Belarus," the report said.

Eritrea allows only state news media, which are controlled by the Ministry of Information, the CPJ said. Journalists have no editorial freedom and follow instructions to cover a story. It said those who send news abroad are thrown in prison and held for extended period of time without access to family or lawyers.

The CPJ said runners-up to the 2012 list were Azerbaijan, Ethiopia, China, Sudan, Turkmenistan and Vietnam.

Syria and Iran have since last year intensified significantly censorship in response to popular uprisings, including barring international media and attacking their own domestic news outfits.

At least nine journalists have been killed while on duty in Syria since November and six others died in circumstances in which "government culpability is suspected," the CPJ said.

It said Iran has one of the world's toughest internet censorship regimes, using mass imprisonment of journalists to silence the opposition and quash critical news coverage.

"The censorship of the media existed far before the revolution, but it has increased since because (President Bashar) Assad wants to convey a particular picture to the outside world that the regime is fighting off terrorists who are causing the unrest," Eiad Shurbaji, a Syrian journalist who fled the country in January for fear of his life, told the CPJ.

"Another tenet of Syria's propaganda was that minorities would beat risk without the regime," Shurbaji said. "Media censorship played a huge role in keeping Assad in power."

The North Korean government controls the contents of the country's12 main newspapers, 20 magazines and broadcasters, the report said. The ruling elite has access to the World Wide Web, but the general public is limited to government information.

Some countries in the 2012 list were already in the 2006 list. They were North Korea, Myanmar, Turkmenistan, Equatorial Guinea, Libya, Eritrea, Cuba, Uzbekistan, Syria and Belarus. (DPA)