Followers of radical Shi'ite cleric Moqtada al-Sadr handed over a captive American hostage to the United Nations after more than nine months of his imprisonment, Sadr's office said on Sunday.
"Leader of Sadr movement Moqtada al-Sadr ordered the military wing of the movement, Kata'ib al-Yom al-Maoud (or the Promised Day Brigades), to release the American soldier Randy Micheal," the office said in a statement posted on its website.
The handover took place on Saturday when the UN mission in Baghdad received the captive from officials and members of parliament from Sadr movement, and the mission handed him over to the U.S. embassy in the Iraqi capital.
"The release of the soldier was without any compensation and was a gift from Sadr to the soldier's family and to his people to show the humanitarian values of the Iraqi Islamic resistance," the statement said.
Sadr loyalists identified the captive as a 59-year-old ex-army sergeant who participated with the U.S. forces in their clashes with Sadr's Mahdi Army militia in the holy Shi'ite city of Najaf in 2004 and in the clashes in Sadr City district in eastern Baghdad in 2008.
However, media reports said that U.S. officials had said none of their serving troops have been listed as hostage in Iraq since they received the remains of a U.S. soldier last month.
The U.S. embassy in Baghdad confirmed it has received an American citizen from the UN mission in Baghdad and is verifying his identity, the reports said.
Sadr gained popularity among younger Shi'ite Iraqis by his anti- American rhetoric since the toppling of former President Saddam Hussein's government by the 2003 U.S.-led invasion of Iraq.
His Mahdi Army militia has been fighting against U.S. troops and was one of the major forces in the sectarian strife in Iraq that claimed the lives of hundreds of thousands of Iraqis.