The US authorities have said on Sunday that three of its citizens were reportedly abducted in the capital city of Iraq, Baghdad.
Abduction of foreign hostages in Baghdad and other parts of Iraq has become a major problem for different nationals living in the war-torn country.
"We are aware of reports that American citizens are missing in Iraq," US State Department spokesman John Kirby said.
"We are working with the full cooperation of the Iraqi authorities to locate and recover the individuals," Kirby added. However, he has not provided full details of the abducted victims.
The Iraqi forces have launched an operation to find the three Americans and an Iraqi translator who were kidnapped in southern Baghdad, according to a police officer, who spoke on condition of anonymity.
The officer added that according to the gathered information, the kidnappers were militiamen wearing military uniforms.
He said, "We don't know what their work is," referring to the kidnapped Americans.
The three US citizens that were reported missing in Baghdad have been abducted, two members of parliament told Reuters on Monday.
The three were invited on Friday to a private event in the Dora district southeast of the capital when they were kidnapped by unknown gunmen, said Mohammed al-Karbouli who sits on the security and defence panel of parliament.
Another member of the same panel, Iskandar Witwit, gave a similar account, saying that they were kidnapped from the Sihha apartment buildings in the Dora district.
Iraqi police and US authorities earlier said three US nationals had been reported missing in Baghdad. The police said it was investigating reports they were kidnapped.
Iraq has turned to paramilitary forces dominated by Iran-backed Shiite militias alongside US-led coalition to help fight DAESH, which control significant parts of Iraq.
Groups which formed an organisation known as the Hashed al-Shaabi or popular mobilisation, have played a key role in fighting against DAESH however, they have also been accused of abuses including extrajudicial executions, kidnappings and destruction of properties.