A rebellious attack that targeted an American outpost in eastern Afghanistan, killing nine soldiers, has intensified distrusts regarding the U.S. military’s attempts to suppress Islamic militants and keep locals on its side.

On early Sunday, approximately 200 fighters encircled the recently built U.S. base in a distant area close to the Pakistan border without being noticed by the troops inside, according to Gen. Mohammad Qasim Jangalbagh, the provincial police chief.

The consequence was the deadliest episode for U.S. forces in Afghanistan since June 2005, when 16 American soldiers were murdered as a rocket-propelled grenade destroyed their helicopter.

Hostility has been growing in Afghanistan, and many people are querying whether the Taliban-led insurgency is achieving and not consuming force seven years after the uncompromising Islamic regime was ousted by a U.S.-managed raid.

The assault added force to recent evaluations made by U.S. officials regarding the fact that militant attacks are becoming more complex and even better organized. Although U.S. and NATO officials said the attack took place in Kunar province, Afghan authorities declared that it happened in adjacent Nuristan.

According to the Associated Press, an official who made his declaration on condition of anonymity, since he was not permitted to make the information public, informed the reporters that the militants had assailed the small U.S. base with machine guns, rocket-propelled grenades and mortar shells. 

In Washington, State Department spokesman Sean McCormack communicated his regret regarding the losses, but claimed the attack was a signal of the tension hanging on the rebel’s shoulders.

However, U.S. military officials have announced that the number of attacks in Eastern Afghanistan have grown with 40 percent compared to last year.

U.S. authorities are taking into consideration the withdrawal of additional forces from Iraq in the next months, because of the need for supplementary troops in Afghanistan. Furthermore, U.S. officials have said they need at least three more brigades in Afghanistan, or over 10,000 soldiers.