Militants who said they belong to a group that has claimed responsibility for kidnappings and killings in Iraq beheaded a man identified only as a Bulgarian in a video posted on the Internet Monday.

The images were indistinct, making it difficult to identify the victim. The militants in the video said they were from the Tawhid and Jihad (search) group, which had claimed to have kidnapped two Bulgarian truck drivers June 29 and demanded Iraqi detainees be released in exchange for their lives.

The beheaded body of one of the drivers, Georgi Lazov, was found in the Tigris River in Iraq in mid July and a tape was released showing his death. An announcement late last month of the discovery of a second decapitated body in an orange jumpsuit and a head in a bag near the Tigris River had prompted fears Kepov too had been killed, but there was no video of his slaying.

The Bulgarian Foreign Ministry said Monday that it had no reliable information on Kepov's fate and that it was still awaiting results from a DNA analysis of the second body found. Previous Web statements signed Tawhid and Jihad had threatened to kill Kepov as well and post images of the killing on the Internet.

In the new video, a bearded, blindfolded man sits before four masked men clad in black and a black banner with the words Tawhid and Jihad in white Arabic script. The hostage is wearing the orange jumpsuit that has become an iconic element in such videos, meant to evoke those worn by Iraqi prisoners subjected to abuse while in U.S. custody in Iraq.

A man is heard saying, "Here we are returning again to cut off the neck of the other hostage."

The brief video ends with bloody images of a body in an orange jumpsuit being beheaded with a knife as his assailants repeatedly shout "God is great!" The victim does not appear to struggle, indicating he may have been dead or drugged before the beheading, or that his arms were somehow restrained. In the last scene, one of the men in black brandishes the severed head before the camera.

Bulgarian officials said Monday they had examined the video but were "unable to identify the executed man because of the material's bad quality."

"Led by our principle not to become a tool in terrorists' hands and by our deep respect for the feelings of the hostages' relatives, we will not comment further on the video material," the Bulgarian Foreign Ministry added in a statement.

It was not clear when the video was made and its authenticity could not immediately be verified. The video was posted on several Web sites known for carrying militant Islamic comment and images.

Tawhid and Jihad's name refers to the Islamic tenets of monotheism and holy war. The group is believed led by Jordanian terror suspect Abu Musab al-Zarqawi (search) and has also claimed responsibility for the beheadings of U.S. businessman Nicholas Berg (search) and South Korean translator Kim Sun-il (search).