The tape, aired on Sunday, showed marks of gunshots on the bodies and a number of Iraqis surrounding them. It also showed a damaged car, which the narrator claimed belonged to the dead men.
On Saturday, Aljazeera aired a tape showing a US detainee kidnapped by a group called al-Mujahidin during an attack on a US convoy.
The captive, Thomas Hamil, is an American working for a private company supporting the military operation.
The convoy, transporting supplies and fuel, was attacked on the Baghdad-Falluja highway on Friday.
The captive said on the tape that he was the only member of the convoy to escape death. He said he was being treated well.
Aljazeera also aired an audio tape from the kidnappers. "Up to now your prisoner is being dealt with in the tolerant manner specified by Islamic law. Our one request is to break the siege of the city of the mosques (in Falluja) during the 12 hours from six o'clock on Saturday evening," the kidnappers said.
"If not, he will be dealt with worse that those who were
killed and burned in Falluja," they added.
A number of people of different nationalities have been reportedly kidnapped in Iraq.
Hamil works for a company
supporting the military operation
Three Japanese, a Palestinian and a Canadian of Syrian origin are all confirmed to having been kidnapped. All of them, except a Japanese freelance photojournalist, are aid workers.
Another seven South Korean pastors were also taken hostage before being released.
Meanwhile, a Briton who went missing in the southern city of Nasiriya six days ago was released on Sunday, reported Aljazeera's correspondent Hamid al-Shutri.
Gary Teeley, 37, was released after tribal leaders in the area negotiated with captors. Teeley, an employee of the International Qatar Company in Baghdad, was handed over to occupation authorities.
Two German security officials who disappeared after coming under attack while travelling from Jordan to Baghdad last week have probably been killed, a German Foreign Ministry spokeswoman said on Sunday.
The two had been on their way to the German embassy in
Baghdad when their convoy was attacked on Wednesday. The incident was not made public until Saturday.