Four NATO soldiers killed in Afghan operation

Four NATO soldiers were killed early Sunday in an operation in Afghanistan, the coalition forces said.

"Four International Security Assistance Force (ISAF) service members were killed by enemy forces during a partnered operation in southern Afghanistan today," the ISAF said in a statement, reports Xinhua.

Troops mainly from the US, Britain and Australia have been stationed in Afghanistan.

On Saturday, one foreign soldier died when an alleged contracted security guard shot him down.

More than 87,000 NATO-led forces, including 60,000 Americans, are serving in militancy-hit Afghanistan.

The latest casualties have brought the number of foreign soldiers killed in Afghanistan to 140 this year.