A group led by al Qaeda ally Abu Musab al-Zarqawi appealed on Friday to Iraqi militants holding Irish aid worker Ms Margaret Hassan to free her unless she was proven to be a spy, a message posted on an Islamic Web site said.
The unknown militant group holding Ms Hassan, director of Care International's now halted operations in Iraq, has threatened to turn her over to Zarqawi's group unless British troops quit Iraq.
"We call on those responsible for her abduction to free her ... unless there is proof of her being an agent," Zarqawi's group said in the message.
It said the captors were obligated to publish any evidence they might hold against her. The message could not be immediately authenticated.
"Those who use this hostage like a playing card have not understood our religion well," the message said.
"We announce to the whole world that if they hand over this hostage to us we would release her immediately unless it is proven that she plotted against Muslims," it added.
Zarqawi's Al Qaeda Organisation of Holy War in Iraq has claimed responsibility for hostage beheadings and some of Iraq's bloodiest suicide attacks.
Dublin-born Ms Hassan, who was seized in Baghdad on October 19th, has an Iraqi husband and has lived in Iraq for 30 years. She holds British and Iraqi passports.
Militants have waged a campaign of kidnappings and killings to try to force US-led troops and foreigners to leave Iraq. More than 35 foreign hostages have been killed.