Two British military personnel were killed when their helicopter crashed in Iraq, the Ministry of Defence (MoD) said.
Two other people were seriously injured when the RAF Puma aircraft came down near Baghdad last night.
The MoD said it was too early to speculate on what caused the crash, but an RAF Board of Inquiry has been set up to investigate the incident. The next of kin of those involved have been informed.
The US military issued a statement saying a coalition helicopter had crashed near Salman Pak, on the outskirts of the Iraqi capital, killing two people and injuring 12. Initial reports indicated that the crash was not caused by hostile fire, the Americans said.
The latest deaths bring to 173 the number of British military fatalities since hostilities began in Iraq in March 2003.