A videotape showing several Arab men seated at gunpoint — purportedly kidnapped Iraqi soldiers — was aired on an Arabic television station Sunday, and the announcer said they were threatened with death unless a detained Shiite leader is freed within 48 hours.

The video was from a group calling itself the Brigades of Mohammed bin Abdullah (search) and claimed to have 18 captive members of the Iraqi National Guard, according to Al-Jazeera television, which obtained a copy of it.

The brief video clip aired by the station showed men in military dress sitting on the floor, with men standing behind them pointing guns to their heads. Most of the hostages had their heads bowed, but they were not blindfolded and appeared uninjured.

No audio was aired, but Al-Jazeera's announcer said the militants threatened to kill them unless Hazem al-A'araji, a member of rebel Shiite cleric Muqtada al-Sadr's (search) office in Baghdad, was released within 48 hours.

U.S. forces and soldiers from Iraq's national guard raided the Baghdad houses al-A'araji and another senior al-Sadr aide, Raed al-Khadumi, on Saturday. Al-A'araji and his brother were detained.

The raid came as a new round of talks with al-Sadr's militia rejected demands to disband and turn in their weapons in a poor Baghdad neighborhood called Sadr City (search). Dozens have died in sporadic clashes between U.S. forces and militiamen in Sadr City.

It was not clear where the hostages were taken or when the deadline expires.

An Al-Jazeera producer told The Associated Press the station received the tape Sunday.