Four NATO soldiers died in Afghanistan's restive southern region on Saturday, the military alliance said on Sunday.

"Four International Security Assistance Force service members died as a result of non-battle related injuries in southern Afghanistan yesterday," said a statement released by NATO-led International Security Assistance Force (ISAF) here.

However, the brief statement did not provide more details.

ISAF generally does not disclose the identity of the casualties, saying "it is ISAF policy to defer casualty identification procedures to the relevant national authorities."

Troops mainly from the United States, Britain, Canada and Australia have been stationed in the southern region within the framework of ISAF to fight Taliban militants.

A total of 249 NATO soldiers, most of them Americans, have been killed in Afghanistan since the beginning of this year.