On Saturday four US soldiers were killed by a roadside bomb in Southern Afghanistan.
The deaths bring to 396 the toll of foreign soldiers killed so far this year, compared to 520 for all of 2009.
The icasualties.org website puts the number of soldiers to have died since the Afghan insurgency began in 2001 at 1,964, with 1,204 of them Americans.
Al Jazeera's Clayton Swisher has been on patrol with US troops in the Arghandab river valley, used by the Taliban to stage attacks in neighbouring Kandahar.
He reports on the perseverance of the 82nd Airborne Division soldiers.