Egypt has become one of the deadliest places in the world for journalists, says the New York-based Committee to Protect Journalists (CPJ).

In an annual report on the issue, the CPJ says six journalists were killed for their work in Egypt in 2013.

The report said that "things deteriorated dramatically for journalists in Egypt" during the year, amid "stark political polarization and related street violence...

"Three were killed in a single day, August 14, as they covered raids by Egyptian security forces on demonstrating supporters of ousted President Mohamed Morsi and the Muslim Brotherhood."

Nine of the 10 journalists killed in Egypt since 1992 have died since anti-government protests began in 2011.

Syria has been the most dangerous place for journalists to work in both 2012 and 2013. While Pakistan and Somalia were the second and third most deadly countries in 2012, they were replaced in 2013 by Iraq and Egypt.

"While Somalia continues to be a very dangerous place to practice journalism," the CPJ says, "the number of confirmed work-related deaths declined to four, plus one media worker, in 2013, compared with a record 12 in 2012. In both years, all of the victims were singled out for murder."

The report adds that although the Somali government has repeatedly pledged to fight "the cycle of impunity in journalists' killings," it has made "almost no progress in solving any of the crimes. In the meantime, CPJ research shows that journalists have stepped up their own security measures, while political groups and Al-Shabaab insurgents — believed responsible for many of the murders — have wielded less lethal influence since 2012 elections."

The CPJ report shows that, across the world, at least 70 journalists were killed for their work during the year, compared with 74 in 2012.

The Middle East accounted for two-thirds of the deaths. At least 29 died as a result of the conflict in Syria, and 10 in Iraq. The CPJ says most journalists who die for their work are local people covering local stories.