Two US helicopters crashed in southwestern Baghdad on Saturday, killing two US soldiers and wounding two others, the US military said.
The incident, which occurred around 8:30 pm (1730 GMT), was under investigation and the cause was not immediately known, it said.
US helicopters flying over insurgent areas often come under attack, with some choppers shot down by surface-to-air missiles or rocket-propelled grenades.
Source: Xinhua