Six soldiers from the US-led NATO mission fighting Taliban insurgents in Afghanistan were killed in an aircraft crash on Tuesday, NATO officials said, adding it was not a suspected militant strike.

The Taliban immediately claimed responsibility for the deaths, saying their fighters had shot down a US helicopter in the province of Zabul.

"Six International Security Assistance Force (ISAF) service members died following an aircraft crash in southern Afghanistan today," an ISAF statement said, declining to give the nationalities of the victims.

"The cause of the crash is under investigation, however initial reporting indicates there was no enemy activity in the area at the time of the crash.

"It is ISAF policy to defer casualty identification procedures to the relevant national authorities."

AFP