Four soldiers of the NATO-led coalition were killed early Sunday morning in a operation in Afghanistan, the coalition forces confirmed in a statement. \"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, Xinhua reported. The statement gave neither the nationalities of the victims nor the details about the incident under the ISAF policy. Troops mainly from the United States, Britain and Australia have been stationed in the Southern region. The Taliban-led insurgency has been rampant since the militant group launched rebel offensive in April against Afghan government forces and about 78,000 NATO-led troops stationed in the country. On Saturday, one foreign soldier died when an alleged contracted security guard shot him also at the same region. The latest casualties have brought the number of foreign soldiers killed in Afghanistan to 140 this year.