WASHINGTON — A U.S. military investigation says command failures left American soldiers in an indefensible position without adequate support when hundreds of insurgents attacked their remote outpost in northeastern Afghanistan with rocket-propelled grenades, mortars and guns.

Eight troops died.

Twenty-two others were wounded during the October 2009 attack on Combat Outpost Keating, one the deadliest battles during the nearly decade-long war. The investigation released today by U.S. Central Command in Tampa, Fla., recommended giving four officers letters of admonition or reprimand for putting the 53 American troops in a vulnerable position at the outpost in mountainous Nuristan province near the Pakistan border.

Documents show Stanley McChrystal, then the top American general in Afghanistan, approved the decision to punish the officers — a captain, a major, a lieutenant colonel and a colonel. For their privacy, their names were removed from the copy of the report posted on Central Command’s website.

The investigation says the soldiers from B Troop, 3rd Squadron, 61st Cavalry, were in a “tactically indefensible position” with an “unclear mission.”