An American soldier who was kidnapped this week in Baghdad had left his base to visit his secret Iraqi wife, a relative told AFP on condition the family not be identified.
A US soldier of Iraqi descent slipped out of Baghdad's heavily-fortified Green Zone on Monday, as Iraqis celebrated the feast of Eid al-Fitr, and has not been seen by his commanders since, the US military has said.
According to relatives, the soldier was visiting his wife at a family home in the downtown Karrada district of the Iraqi capital when masked gunmen in three cars stormed the building and kidnapped him.
One of the relatives, an Iraqi, told AFP the American had married an Iraqi woman in secret. "The family were against the marriage, it was thought she had bad morals," he said on Saturday.
The relative said some in the family suspected the wife might have been to blame for the abduction, either by deliberately tipping off the kidnappers or by "talking too much" about the supposedly secret liaison.
The kidnapping has triggered a massive manhunt by thousands of US soldiers, who have set up cordons and checkpoints around Baghdad and have carried out raids and searches at several locations in the city.
During one search of the Sadr City, a bastion of the Mahdi Army militia, a battle erupted in which Iraqi government forces and US advisers killed at least 10 militants.
The US military has not identified the missing soldier in order to protect his safety and that of his family. He worked as a linguist with a military reconstruction team based in Baghdad, according to a US spokesman.
"Cordon and checkpoint operations will be conducted today and operations to find our missing soldier continue," a US spokeswoman said.