Six NATO service members have been killed in a helicopter crash in southern Afghanistan, NATO said in a press release Friday morning.

The ISAF helicopter crashed in S. Afghanistan on Thursday, killing six NATO service members on board, the NATO-led ISAF forces said.

"I confirm that there was a helicopter crash in southern Afghanistan on Thursday, killing six NATO service members on board. However, there is no reported enemy activity in that area," a spokesperson said.

The spokesperson, however, did not provide details and the nationalities of the victims, only saying "it is ISAF policy to defer casualty identification procedures to the relevant national authorities."

ISAF has started to investigate into the incident.