Topeka ? A sixth Fort Riley soldier has died as a result of a June 6 incident in Iraq, making it the single deadliest attack on a unit from the post since the war started more than eight years ago.

The Department of Defense said Saturday that Spc. Marcos A. Cintron, 32, of Orlando, Fla., died Thursday in a hospital in Boston where the 1st Infantry Division soldier was being treated for his wounds.

The deaths from June 6 surpass those in a 2004 attack to become the highest single-day casualties for Fort Riley soldiers since the wars in Iraq and Afghanistan began. Five soldiers of the 1st Battalion, 1st Engineer Battalion were killed on March 31, 2004, in Iraq.

Cintron and the five other soldiers were attacked June 6 by insurgents using indirect fire in Baghdad. They were assigned to the 1st Battalion, 7th Field Artillery Regiment, 2nd Heavy Brigade Combat Team.