Four service members were killed as a chopper of NATO-led International Security Assistance Force (ISAF) crashed in Afghanistan's southern Helmand province on Wednesday, a statement of the alliance said.

"Four ISAF service members were killed after their helicopter was brought down by hostile fire in Helmand province, southern Afghanistan, today," the statement said.

However, the statement did not identify the nationality of the victims, saying "It is ISAF policy to defer casualty notification procedures to the relevant national authority."

Taliban militants claimed of responsibility for the attack.

A Taliban purported spokesman Qari Yusuf Ahmadi in talks with media via telephone from undisclosed location said the militants shot down the chopper killing over a dozen on board at 01:00 a.m. local time.

It was a Chinook helicopter and went down in Sangin bazaar, he further said.

So far this year 245 service members of NATO-led troops have been killed in the militancy-plagued Afghanistan.