The number of journalists imprisoned worldwide reached a record high in 2012, according to the Committee to Protect Journalists.
The group said the increase was driven in part by the widespread use of antiterrorism laws to prosecute reporters critical of governments that abused their power.
CPJ said there were 232 journalists imprisoned worldwide, an increase of 53 over 2011. That was the highest number since the group began conducting surveys in 1990. The previous record - 185 - was set in 1996.
Three countries - China, Iran and Turkey - were the worst offenders. The three "each made extensive use of vague anti-state laws to silence dissenting political views, including those expressed by ethnic minorities. Worldwide, anti-state charges such as terrorism, treason, and subversion were the most common allegations brought against journalists in 2012," CPJ said.
Syria and Eritrea were not far behind. Vietnam, Azerbaijan, Ethiopia, Uzbekistan and Saudi Arabia rounded out the top 10.
Some highlights of the CPJ report:
• Turkey alone had jailed 49 journalists, including dozens of Kurdish reporters and editors held on terror-related charges and others charged with plotting against the government. Turkey's laws "make no distinction between journalists exercising freedom of expression and [individuals] aiding terrorism," said Mehmet Ali Birand, a top editor with the Istanbul-based station Kanal D.
• Iran has 45 journalists behind bars and is the second-worst country on the list. It has been cracking down on journalists ever since the bitterly divisive 2009 presidential election. One example: Zhila Bani-Yaghoub, an editor of a website focusing on women's issues, is serving a one-year sentence on charges of "propagating against the regime" and "insulting the president."
• China, third-worst on the list, has 32 journalists locked up. The country has routinely jailed writers critical of the government. Those held to include Dhondup Wangchen, a documentary filmmaker jailed after interviewing Tibetans about their lives under Chinese rule.
"Journalists who report on areas deemed 'most sensitive' by the state - China's troubled ethnic regions of Tibet and Xinjiang - are most vulnerable," said Phelim Kine, deputy director of the Asia division of Human Rights Watch.
• Eritrea, fourth-worst jailer of journalists, is holding 28. "No Eritrean detainee has ever been publicly charged with a crime or brought before a court for trial," CPJ said. "President Isaias Afwerki's government has refused to account for the whereabouts, legal status, or health of the jailed journalists, or even confirm reports that as many as five have died in custody due to inhumane treatment."
• Meanwhile Syria, fifth-worst on the list, is believed to be holding American freelance journalist Austin Tice, who had been covering the civil war there for several news outlets including The Washington Post, McClatchy and Al-Jazeera English. None of those held in Syria have been charged with a crime, and the government of President Bashar al-Assad has refused to provide details of the detainees' whereabouts or well-being.
• No. 6 Vietnam, where 14 reporters are in custody, tends to target online journalists who write about such politically sensitive topics as the country's relations with China and its treatment of the Catholic community, CPJ said.
For example, three Vietnamese journalists recently received prison sentences ranging from four to 12 years for posting blog entries that criticized the Communist government. Not only that, the three face three to five years under house arrest after their jail sentences are done.
CPJ said most of those being held are local journalists. Print and online reporters were jailed more often than broadcast journalists, the group said.
"CPJ believes that journalists should not be imprisoned for doing their jobs," the survey's authors wrote. They said the group had sent letters expressing its concerns to governments that had imprisoned journalists, and that such advocacy had resulted in the early release of at least 58 imprisoned journalists in the past year.