The northern Iraqi city of Mosul has become a nightmare for journalists, with five killed since October with alleged impunity, pushing some to flee the area or even the country.

Iraq has come in for repeated criticism over the lack of media freedom and the number of unsolved killings of journalists.

But the series of attacks on journalists in Mosul, with the latest on Sunday, when gunmen shot dead TV presenter Nawras al-Nuaimi, is the worst to hit Iraq in years.

"I had to change my place of residence in Mosul and remain at my (new) home without leaving, after the killings that affected a number of my colleagues," said journalist Salim Fadhel, 30.

"My colleagues left Mosul for the Kurdistan region with their families, or for outside Iraq," Fadhel said, referring to the autonomous three-province region of northern Iraq where attacks are relatively rare compared to the rest of the country.

"There is a rumour in Mosul saying that armed groups issued a list of names of 40 journalists who will be eliminated by them," Fadhel added.

Nuaimi, a presenter in her late teens for Al-Mosuliyah TV, was the sixth journalist to be killed in Iraq since October, of whom five died in Mosul.

"We are stunned by this latest murder and by the failure of the local and national authorities to respond to the deadly campaign against journalists in Iraq," media rights watchdog Reporters Without Borders said in a statement on the killing of Nuaimi.

"The continuing violence and the impunity enjoyed by those responsible constitute a major threat to freedom of information," it said.

Nuaimi's death came after that of Alaa Edwar, a Christian journalist working for the Nineveh al-Ghad television network, who was shot dead in Mosul in November.

And Al-Mosuliyah cameraman Bashar Abdulqader Najm and two journalists from Sharqiya television channel -- correspondent Mohammed Karim al-Badrani and cameraman Mohammed Ghanem -- were killed in Mosul in October.

Mosul, the capital of Nineveh province, is one of the most dangerous cities in Iraq, with militants frequently carrying out attacks and reportedly extorting money from shopkeepers.

And Iraq as a whole has come in for repeated criticism from media rights groups.

"Many Iraqi journalists are routinely exposed to threats, murder attempts, attacks, difficulties obtaining permission, denial of access, confiscation of equipment and so on," Reporters Without Borders said earlier this year.

Another journalist, Kawa Ahmed Germyani, was shot dead earlier this month in front of his mother in Iraq's Kurdistan region.

'Astonished by weakness'

Ban al-Obaidi, the Mosul representative of an Iraqi media rights group, said its efforts are limited to issuing condemnations when attacks or other violations occur, "because of the lack of interest of relevant government agencies."

"Fifty journalists or media (employees) have been killed in the province of Nineveh at the hands of unknown (people) since 2003," and others have been wounded or disabled, she said.

"We are astonished by the weakness of the security forces and the local government, which appear helpless in front of the killing and targeting of journalists that is happening without them moving a finger to protect them," said Fadhel, the journalist.

Authorities should "at least arrest some of those who carry out killings, to find out who is behind them," he said.

Adhawi al-Suaib, a member of the Nineveh provincial council's culture committee, which is responsible for handling issues related to journalists, admitted it is unable to protect them.

"We recognise our inability to do what is necessary to ensure journalists in Mosul are protected," Suaib told AFP.

"We are not even able to protect ourselves."