 To quell the rebellion , Cuban government troops began executing rebel prisoners on the spot , and regularly rounded up , tortured , and shot civilians as a tactic of intimidation . By March 1958 , the continued atrocities carried out by Batista 's forces led the United States to announce it would stop selling arms to the Cuban government . Then in late July 1958 , Guevara played a critical role in the Battle of Las Mercedes by using his column to halt a force of 1 @,@ 500 men called up by Batista 's General Cantillo in a plan to encircle and destroy Castro 's forces . Years later , Major Larry Bockman of the United States Marine Corps would analyze and describe Che 's tactical appreciation of this battle as " brilliant " . During this time Guevara also became an " expert " at leading hit @-@ and @-@ run tactics against Batista 's army , and then fading back into the countryside before the army could counterattack . 
