A militant group's claim that it had kidnapped a U.S. soldier in Iraq and planned to behead him was suspected of being a hoax yesterday, after a California toy manufacturer said photos of the purported captive on an insurgent Web site appeared to show one of its collectible dolls.

A group calling itself the Mujahedeen Brigades posted a photograph that appeared to show a stern-faced U.S. soldier sitting at gunpoint before a black banner with Arabic script. The posting called the soldier "John Adam."

U.S. military authorities said aspects of the photograph raised doubts: The soldier's vest, for instance, resembled no such equipment issued by the Army, and the claim on the Web site about the kidnapping appeared to contain misspellings. Nevertheless, they asked for a full accounting of military personnel in Iraq.

"No units have reported anyone missing," Staff Sgt. Nick Minecci of the military's press office in Baghdad told The Associated Press.

In the grainy photograph, the figure appears dressed in desert camouflage and leans stiffly against a concrete wall with his hands behind him. He wears a bulky vest and green kneepads. The barrel of an American automatic rifle is pointed at his head, but no one is pictured holding the weapon.

An executive for Dragon Models USA said the soldier looked exactly like a foot-tall G.I. Joe-type doll the company manufactured for sale at U.S. bases in Kuwait.

"This looks like our doll," said Liam Cusack, a company spokesman. "We don't want to say 100 percent that it is our doll, but it does bear a striking resemblance. We're hoping that this is actually a hoax."

Cusack said the doll appeared to be the black version of its "Cody" action figure, one of several thousand sold to U.S. military bases in Kuwait about three years ago. The dolls are minutely detailed and frequently used in dioramas of war scenes.

Cusack said he was alerted to the photograph yesterday by a retailer who saw the photo on a news Web site. Cusack said he had not had contact with the U.S. military about the matter.

The Mujahedeen Brigades claimed responsibility for two abductions last April. One involved three Japanese, who were later released, and the other a Brazilian engineer. It was unclear yesterday whether that group, or someone else, was behind the apparently fake photos.

To date, only one U.S. soldier has been confirmed taken hostage by insurgents: Pfc. Keith M. Maupin, 20, of Batavia, Ohio. Maupin was shown in a hostage video in April. A second video in June purported to show his execution, but the military still lists him as missing.