A U.S. soldier from Alpha Co, 2nd Battalion 35th Infantry, Task Force “Cacti” scans the area through the scope of his rifle while on patrol in a village near Brabat border checkpoint at the Afghanistan-Pakistan border in Kunar province October 5, 2011. (REUTERS/Erik De Castro)

A U.S. soldier from Alpha Co, 2nd Battalion 35th Infantry, Task Force “Cacti”, throws away the empty shell of a 120mm mortar after firing successive rounds at Taliban positions in Shalay Valley from Combat Outpost Penich, in Kunar province, near the Afghanistan-Pakistan border October 4, 2011. (REUTERS/Erik De Castro)

A U.S. soldier from Alpha Co, 2nd Battalion 35th Infantry, Task Force “Cacti” stands guard with Afghan Border Police on patrol near Brabat border checkpoint at the Afghanistan-Pakistan border in Kunar province October 5, 2011. (REUTERS/Erik De Castro)

U.S. soldiers from Alpha Co, 2nd Battalion 35th Infantry, Task Force “Cacti”, fire a 120mm mortar round at Taliban positions from Combat Outpost Penich in Shalay Valley, in Kunar province, near the Afghanistan-Pakistan border October 4, 2011. (REUTERS/Erik De Castro)

Residents look at a U.S. soldier from Alpha Co, 2nd Battalion 35th Infantry, Task Force “Cacti” on patrol along a road near the Brabat border checkpoint at the Afghanistan-Pakistan border in Kunar province October 5, 2011. (REUTERS/Erik De Castro)

U.S. military officer 1LT Adam Ferree (C), 1st Pltn leader, from Alpha Co, 2nd Battalion 35th Infantry, Task Force “Cacti” gives a command to the rear plank during a joint military patrol in Walay valley, near the Afghanistan-Pakistan border in Kunar province, October 2, 2011. Picture taken October 2, 2011. (REUTERS/Erik De Castro)

U.S. soldiers from Alpha Co, 2nd Battalion 35th Infantry, Task Force “Cacti”, fire a 120mm mortar round at Taliban positions in Shalay Valley from Combat Outpost Penich, in Kunar province, near the Afghanistan-Pakistan border October 4, 2011. (REUTERS/Erik De Castro)

U.S. soldiers from Alpha Co, 2nd Battalion 35th Infantry, Task Force “Cacti” fire 120mm mortar at Taliban positions in Shalay Valley from Combat Outpost Penich near the Afghanistan-Pakistan border in Kunar province October 4, 2011. (REUTERS/Erik De Castro)

A U.S. soldier from Alpha Co, 2nd Battalion 35th Infantry, Task Force “Cacti” stands guard while on patrol in a village near Brabat border checkpoint at the Afghanistan-Pakistan border in Kunar province October 5, 2011. (REUTERS/Erik De Castro)