There are conflicting reports about the fate of at least 30 Iraqi policemen in western Iraq.
The group was apparently ambushed by 20 armed men in the town of Rutbah, near the Jordanian border, on Sunday.
Reports said the men, many of whom were believed to come from the Diyala province, were seized as they returned home after a training course in Jordan.
Some reports quote police sources in Karbala, but the chief of police in the city said none of his men were missing.
A Karbala police spokesman, who spoke under condition of
anonymity, said earlier that the police officers were seized while they were staying in a hotel in the west of the country.
"There was an attack on a hotel occupied by policemen
coming back from training in Jordan," he told the Associated Press news agency.
Last month, nine Iraqi policemen returning from training in Jordan were ambushed and killed on their way back to Iraq.
Reports of the abduction came as violence continued elsewhere in Iraq.
In the town of Baiji, north of Baghdad, at least 14 Iraqis were killed in a car bomb attack on an American patrol and nine people died in Ramadi.
Clashes have also continued in Falluja, where US marines have been carrying out house-to-house searches but the northern city of Mosul is said to be relatively calm.