By Sebastian Usher
BBC world media correspondent
Paris-based media watchdog Reporters Without Borders is calling on Iraq to set up a special investigation into the upsurge in murders of Iraqi reporters.
In the past three years, 93 media workers have been killed in Iraq
So far this month five journalists and media assistants have been killed.
Last year saw a big increase in the number of Iraqi journalists targeted by gunmen and kidnappers.
The Iraqi security forces have been criticised for doing little to stop the attacks or find the perpetrators.
The dangers for Iraqi journalists have been underlined in the grisliest way in the past few days.
The body of a freelance journalist, Abdel Magid al-Mohammedaoui, was found in Baghdad on 5 May.
On the same day, Saud Mazahem al-Hadithi, a reporter on the satellite TV station al-Baghdadia was found dead days after he had been kidnapped. His family said his body showed the marks of torture.
A car bomb on 7 May at a Baghdad newspaper, al-Sabah, killed a print shop technician and wounded more than 20 others.
The next day, the bodies of a reporter, Muazaz Ahmad Barud and his soundman Leith al-Dulaimi, both working for the TV station al-Nahrain, were found 40km (25 miles) south-east of Baghdad.
Reporters Without Borders says that it can "no longer find words to express its horror at the tragedies constantly suffered by the press in Iraq", noting that 93 journalists have been killed since the start of the war, 18 of those deaths so far in 2006.
"We appeal again to Prime Minister Nouri Maliki to set up a special group of investigators to shed light on the murders of journalists in Iraq," the group said in a statement on its website.
In the past 18 months, Iraqi journalists have come increasingly under attack, partly because they are the most visible reporters still moving around the country now that Western journalists are mostly confined to Baghdad by the dangers facing them.
But it seems clear, too, that militant groups want to stop Iraqi journalists from reporting in any way that contradicts their ideology or propaganda.