Iraqi militants beheaded a man, presumably Iraqi, who said he worked for the U.S. military in the northern city of Mosul (search) for the past 10 months, according to a videotape posted on Islamic Web sites Saturday.

The killing was claimed by the Ansar al-Sunnah Army (search), a group that claimed responsibility for beheading a Turkish driver and an Arab Shiite Muslim in two tapes that surfaced earlier this month and 12 Nepalese construction workers, whose killings were shown in a video posted Aug. 31.

The authenticity of the latest tape and the claim of responsibility could not be independently verified.

The tape posted Saturday showed a man wearing what appeared to be a U.S. military-issue brown T-shirt. Speaking in Arabic, he identified himself as Seif Adnan Kanaan, saying he worked as a vehicle mechanic and beverage deliverer for U.S. forces based at Mosul airport.

The tape showed him with his hands tied behind his back seated in front of three armed, masked militants. The militants were before a black banner with white Arabic script bearing the militant group's name.

One militant described Kanaan as a "crusader spy recruited by the American troops to follow and carry information about the mujahedeen in Mosul." The militant also accused the captive of cursing Islam's Prophet Muhammad (search).

Shortly before he was killed, the hostage said, "I am telling anybody who wants to work with Americans to not work with them. I found out that the mujahadeen have very accurate information [and] strong intelligence about everything. They are stronger than I thought."

The tape then shows a militant slitting the victim's throat before severing his head and placing it on his back. The tape did not specify the man's nationality, but he appeared to be Iraqi. It was unclear when he was captured or killed.

In their campaign to force U.S.-led forces out of Iraq, insurgents have targeted people, including Arabs, they regard as supporting the American military.

Insurgents also have killed foreign hostages, including several Americans.