The tape showed a masked man shooting the hostage while he was seated in a chair. When the man fell to the ground, the gunman shot him two more times with a pistol while shouting "God is Greatest," the Telegraph said.

Reports said it was not clear when the hostage- who identified himself as Murat Yuce from Ankara--was killed.

The hostage spoke in Turkish while three masked gunmen stood in front of a banner resembling that of Zarqawi's Tawhid and Jihad Group. Some sites also carried still pictures depicting the execution.

"Turkey is still insisting on aiding the infidel US operation...We will apply God's law on this apostate and ask Muslims in Turkey to help their Muslim brothers and not the occupation," one gunman said in a statement read out in Arabic.

A number of Turks have been taken hostage in Iraq and at least two have been reported killed. On Saturday Al Jazeera television broadcast a videotape from Zarqawi's group threatening to "apply Islamic law" and behead two Turkish drivers unless their company stopped supplying the US military in Iraq and quit the country completely.