A television image aired by Al Jazeera June 27, 2004 shows a blindfolded man dressed in camouflage sitting in a chair with a hand holding a sword above his head. A Marine Corps identity card named him as Wassef Ali Hassoun. (Reuters photo)

The US military confirmed late Sunday that a Marine corporal named Wassef Ali Hassoun had been missing in Iraq from his unit for nearly a week, but said it was unclear if he had been taken hostage.

US Marine Corporal Wassef Ali Hassoun has been missing in Iraq since last Monday, a spokesman for the US Marine Corps confirmed late Sunday.

"Although we can't confirm that he has been taken hostage, we can confirm that that he has been absent from his unit since June 21," said Major Douglas Powell, spokesman for the US Marine Corps.

Hassoun was attached to the First Marine Expeditionary Force, and his unit was operating west of Fallujah, Powell said, adding that he could not confirm that Hassoun was of Pakistani descent.

Earlier on Sunday, Iraqi militants have allegedly kidnapped a US marine and threatened to behead him unless Iraqi prisoners are released, al-Jazeera Satellite TV reported.

A group, which called itself the "Islamic Retaliation Movement", was quoted as saying that the marine of Pakistani origin would be executed unless detainees in US-led coalition prisons are freed.

The name of the captive was Wassef Ali Hassoun and he was abducted outside a Marine base, the group claimed.

In a video footage aired by Arabiya news channel earlier on Sunday, an unknown armed group announced that it was holding a Pakistani hostage and he would be beheaded if prisoners detained in Iraq are not released in three days.

"You must release our prisoners held in the US base in Balad, Dujail, Yathrib, Samarra and Abu Ghraib and you have three days from now on and after that we will behead him," said the group.

The Pakistani, a driver working with the US-led coalition and entering Iraq from Kuwait, was taken hostage near Balad in northern Iraq, mentioned the group.