The Reuters and NBC employees were detained on Friday near Falluja, west of Baghdad, after resistance fighters shot down an OH-58 Kiowa Warrior helicopter, killing one US soldier and wounding another. The media staff were released on Monday.
Shortly after the helicopter was shot down, the US military said assailants posing as journalists fired upon US soldiers who were guarding the burning aircraft, and that it had detained four suspects.
The US military has said it was investigating, and has not commented on the possibility that soldiers mistook the media men for fighters.
The Reuters employees are Salem Uraiby, a TV cameraman based in Baghdad; Ahmad Muhammad Hussein Badrani, a TV employee based in Falluja; and Sattar Jabar Badrani, a driver based in Falluja.
The NBC cameraman is Ali Muammed Hussayn Badrani.
Alaa Noury, another Reuters driver who was working with the news crew that was later detained, said they had been fired on by US troops as they filmed in the area.
They drove away at high speed and were unhurt, according to Reuters. Noury returned to Baghdad, while his colleagues stayed in the area and were detained.
A total of 13 media people were killed in Iraq in 2003, including Reuters cameraman Taras Protsyuk in April when the hotel he was staying in came under US fire. Mazen Dana, another Reuters cameramen, was also killed in August outside Baghdad.