Footage of what appears to be a Turkish hostage in Iraq being shot dead has appeared on the internet.
The man was blindfolded before being shot
The videotape shows a group of masked men standing over a figure, who is then shot in the head three times.
The man identified himself as Murat Yuce, an employee of Turkish company Bilimtur. The company has confirmed it had an employee by that name.
It is not clear when or where he was kidnapped, or when the apparent killing took place.
Following the tape's release, a Turkish lorry drivers' association announced it had stopped the transport of cargo to US forces in Iraq.
In the video, the man said to be Mr Yuce reads a statement in Turkish, saying: "I have a word of advice for any Turk who wants to come to Iraq to work: You don't have to be holding a gun to be
aiding the occupationist (sic) United States... Turkish
companies should withdraw from Iraq."
Then the leader of the three masked men takes out a pistol and shoots him.
The men are standing in front of a banner which resembles that of Tawhid and Jihad - a militant group reportedly run by Abu Musab
al-Zarqawi, the Jordanian accused of a series of attacks in Iraq.
Before the man spoke, the leader of the group read out a statement in Arabic, saying despite warnings, Turkish firms continued to operate in Iraq "including this apostate, Murat Yuce".
Men claiming to be from the same militant group said on Saturday they had captured two Turkish lorry drivers, and demanded that the men's employers leave Iraq.
FOREIGN HOSTAGES KILLED
14 April: Fabrizio Quattrocchi, 36, Italian security guard is shot dead
11 May: Nick Berg, 26, US businessman is beheaded
22 June: Kim Sun-il, 33, South Korean translator is beheaded
29 June: Keith Maupin, 20, US soldier is reportedly killed (not confirmed)
14 July: Georgi Lazov, 30, Bulgarian truck driver is beheaded
29 July: Pakistanis Azad Hussein Khan and Sajjad Naeem's dead bodies are shown on video
A tape shown on the Arab TV channel Al-Jazeera showed the men's Turkish passports, identifying them as Abdurrahman Demir and Said Unurlu.
On Monday, the owner of the company said he would comply with the demands.
"We have halted all transportation to Iraq," company
chairman Omer Ozturk said. "We are now waiting
anxiously for our drivers to be released."
In its written statement issued on Monday, the Istanbul-based International Transporters' Association said: "It is observed that security and stability in Iraq cannot be maintained yet.
"Within the framework of current developments, UND decided to stop the transport of cargo which belong to the American troops in Iraq as of Monday."