CHILPANCINGO, Mexico (Reuters) - A protest by government workers in a drug violence-riddled southern Mexican city over rotting corpses at the municipal morgue temporarily closed a prosecutor s office on Tuesday, officials said. The protest by some 60 workers forced the office in the city of Chilpancingo, the capital of southern Guerrero state, to shut for about three hours. The protesters complained that overcrowding at the morgue was causing unsanitary conditions. Violence has spiked in Guerrero in recent years as a growing number of criminal gangs vie for control of crops of opium poppies and for drug-trafficking routes. Media reports said that at least 500 corpses were being stored in the morgue. Officials promised protesters that future transfers of bodies to the morgue will involve better sanitary conditions.  Workers in the prosecutor s office will take the necessary precautions so that the situation that occurred today, in which the odor (from the corpses) arrived at the office and caused the workers to stop work, doesn t happen again,  the state government said in a statement.   