A US Army helicopter crashed on a night time mission in southwestern Afghanistan, and initial reports from the scene indicated that as many as four soldiers may have been killed, a US defense official said.
In a brief official announcement, the American military command in Kabul said there were 'no confirmed reports' of casualties 'at this time'.
The announcement did not specify the nationality of the helicopter crew and said the cause of the crash that happened on Thursday, was unknown.
Two US defense officials said four US troops were aboard the helicopter, identified as an Army Black Hawk, and one official said initial word from the scene was that officials 'don't expect' that any of the four survived.
Both officials spoke on condition of anonymity because details were still being collected and the families of the helicopter crew had not yet been notified.
Unspecified weather difficulties may have played a role in the crash, the two officials said, but it also was possible that enemy action was factor.