NATO says a U.S. service member has died as the result of a bomb blast in southern Afghanistan.

The death Sunday marked the sixth U.S. fatality in as many days in the widening war, according to an Associated Press count. No other details were released.

Violence has surged across much of the country since President Barack Obama ordered 21,000 U.S. troops to the country this year, shifting the focus of the U.S.-led war on Islamic extremism from Iraq.

Fifty-one U.S. troops died in Afghanistan in August, the deadliest month in the deadliest year for American forces there since the U.S.-led invasion in late 2001.