Six gunmen wearing police uniforms were allowed to enter the prison by unsuspecting guards who believed the men were delivering another prisoner, state prosecutors said.
"Once inside the prison, the armed group began an attack on inmates and then on guards in a security tower, where four prisoners and five attackers were killed," the Attorney General's office of Guerrero said in a statement.
A prison guard and one of the alleged gunmen remained in hospital with gunshot wounds.
Prison unrest is common in Mexico.... click for images and more info. http://jaketrust..com/2014/01/nine-people-were-killed-during-gunfight.html