The US military in Iraq say a soldier who went missing in Baghdad on Monday night was kidnapped.
US troops are coming under attack more frequently
They say the solider was seized by gunmen when he left the Green Zone, handcuffed and bundled into a vehicle.
The soldier, who has not been named, is an American of Iraqi descent working as a translator for the US military.
The disappearance comes amid a surge in attacks on US troops. More than 80 have died in October - more than in any single month since November 2004.
The military said the soldier was last seen inside the fortified Green Zone compound in Baghdad on Monday afternoon.
He was declared missing at 1930 local time (1730 GMT).
He is believed to have left the Green Zone to visit relatives in the city.
He was reportedly taken while at the relative's house in the central Karradah district, according to the Associated Press news agency.
The US military said it was continuing to seach the area where the man disappeared, erecting a security cordon and passing from house to house with photographs of the man.
Reconnaissance helicopters were seen flying overhead and troops have also raided the al-Furat TV station as part of their efforts.
The last US troops to be reported missing in Iraq, in June, were found murdered and mutilated days later.
An insurgent group with links to al-Qaeda in Iraq said it was responsible for the killings.