SAN JUAN, Puerto Rico (AP) -- The U.S. has rejected a Guantanamo prisoner's proposal to end his 3 1/2-year hunger strike in exchange for easing his conditions at the American prison in Cuba, saying such a deal would undermine security and encourage similar protests. A federal judge in Washington had urged U.S. authorities to consider the proposed deal in the case of Ahmed Zuhair, a Saudi prisoner who has refused to eat since the summer of 2005 and is force-fed a liquid nutrient mix to keep him alive.