Baghdad - Iraqi Prime Minister Nuri al-Maliki ordered an investigation Sunday into the killing of four journalists, according to a cabinet statement.

Those who committed this crime must be brought to justice to receive the just punishment they deserve, the statement said.

The journalists worked for Iraqi TV station al-Sharqia.

Unknown gunmen kidnapped them on Saturday in western Mosul, 405 kilometres north of Baghdad, the Voices of Iraq (VOI) news agency reported.

"They bore gunshot wounds to the head and chest," an unidentified police source told VOI.

The dead were part of a crew of six, who worked on a popular TV programme during the holy month of Ramadan.

The programme interviewed a poor family every day during the time Muslims break their daily Ramadan fast.

The murder of the four journalists brings the number of killed journalists in Iraq to 243. (dpa)