A US helicopter crashed just north of Baghdad today.
The US military confirmed that the helicopter went down but was still investigating the cause of the crash. A military spokesman had no comment on the fate of the crew.
Earlier, witnesses said the aircraft went down after coming under rocket fire in the small town of Mishahda. One witness said US troops surrounded the crash site, where smoke was rising.
Rebels in northern Iraq apparently shot down an armed US reconnaissance helicopter on Friday, killing its two pilots.
Just six days earlier, all 12 people aboard were killed when a Black Hawk helicopter went down close to the nearby northern city of Tal Afar, though that has so far been blamed on weather.
Only three small helicopters were confirmed as being shot down last year, although the causes of some other fatal crashes have not been made public. A British transport plane was brought down a year ago, killing all 10 aboard.
US commanders have warned of a possible increase in violence once the results of last month's parliamentary election are finally announced, probably this week.
Sunni Arab guerrillas are waging an insurgency to try to force US troops out of the country and topple the Shia and Kurdish-led government.