Italy has expressed outrage at the killing of an Italian journalist and Red Cross aid worker, Enzo Baldoni, by kidnappers in Iraq.
Enzo Baldoni was working for a Milan magazine
The Italian foreign ministry said its diplomats in the Gulf had reported seeing video footage of the hostage being shot in the head.
Baldoni reportedly struggled with his captors moments before being killed.
He disappeared on 19 August south of Baghdad. His captors had demanded that Italy withdraw its troops from Iraq.
A group calling itself the Islamic Army in Iraq said it had killed Baldoni, 56, after Italy had refused to pull its 3,000 troops out of Iraq within 48 hours, Arabic al-Jazeera TV reported.
Italian Prime Minister Silvio Berlusconi denounced the killing as an "act of barbarity".
Italy had said it had no intention of pulling out of Iraq but was committed to securing the release of the journalist.
But on Thursday Foreign Minister Franco Frattini offered during a broadcast on al-Jazeera to withdraw the Italian troops from Iraq if requested to do so by the interim government in Baghdad.
The minister will report to parliament in Rome on the latest developments over the killing later on Friday.
Baldoni is the second Italian to be taken hostage and killed in Iraq. An Italian security guard was killed by kidnappers in April.
Reacting to news of Baldoni's death, Mr Berlusconi said: "There are no words to describe this inhuman act that with one blow wipes out centuries of civilisation to bring us back to the dark ages of barbarity."
The body of Baldoni's Iraqi driver was found shortly after the journalist disappeared near the troubled city of Najaf.
Video broadcast by al-Jazeera on Thursday apparently shows Mr Baldoni speaking on camera in front of the group's banner but no audio can be heard.
The channel said it also had footage of the reporter's dead body but would not air it out of respect for his family's feelings.
Baldoni's family had appealed for his safe release
An Italian source who saw the full video obtained by al-Jazeera was quoted by AFP news agency as saying it contained "horrifying pictures".
The journalist's colleagues at Milan weekly magazine Diario were stunned by the report of his death.
"We were so optimistic - we couldn't believe he wouldn't get out," one colleague, Gianni Barbacetto, told AFP.
Baldoni's daughter Gabriella told Italian TV on Wednesday that her father was "trying to save human lives in Najaf by helping a Red Cross convoy, in a spirit of solidarity which has always underscored his thinking and his actions".
Four Italians were taken hostage in Iraq in April. One of them, civilian security guard Fabrizio Quattrocchi, was later shot dead by his captors.
The surviving three were eventually released unharmed.