Officials from the NATO-led International Security Assistance Force in Afghanistan say three service members were killed Sunday in the country's eastern borderlands, the first NATO combat deaths this month.
Troops from various nations serve in eastern Afghanistan, and Sunday's statement did not provide a nationality nor details of the type of attack.
Reuters cited a U.S. official as saying the three casualties were American soldiers, killed by insurgents in Paktia province, an area that borders Pakistan and has endured some of the highest levels of fighting during the U.S.-led 12-year war in Afghanistan.
The deaths bring to 103 the number of foreign troops killed so far this year. Of those, 78 were from the United States.
Foreign combat troops are due to leave Afghanistan at the end of 2014.