( CNN ) -- At least 17 people were killed when inmates tried to escape from a prison in northern Mexico Tuesday , firing guns at guard towers and running through tunnels below the facility . The dead included 11 inmates and six guards , Durango state public safety officials said in a statement . The violence broke out around 5 p.m. Tuesday at a prison in the city of Gomez Palacio when prisoners began to riot and opened fire , officials said . `` The inmates started to shoot with firearms toward the guard towers and the guard areas , '' the statement said . Officials said the clashes occurred as guards worked to stop a `` massive prison break . '' Guards fired shots in the air to try to contain the riot , officials said , then `` exchanged gunfire '' when there was no response . Military troops stopped the attempted prison break , and authorities were investigating to determine who was responsible , the statement said . Violence has been repeatedly reported at the prison where Tuesday 's clashes occurred . In a fight at the prison last year , 11 inmates were killed . In July 2010 , Mexico 's attorney general 's office alleged that inmates from the prison were let out to kill rival drug gang members . At the time , a spokesman for the attorney general 's office said prison officials had allowed a group of inmates to leave the Cereso No . 2 prison in police vehicles to launch an attack at a birthday celebration that left 17 dead . Top prison workers were named as suspects in an investigation . The prison 's former director and 10 others were sentenced in the case . They are now in Mexican federal prisons elsewhere in the country . CNNMexico.com and CNN en EspaÃ±ol 's Karina Maciel contributed to this report .
Clashes break out as guards work to stop a `` massive prison break , '' officials say . 11 inmates and 6 guards are killed , Durango public safety officials report . Violence has been reported at the prison in the past . In 2010 , prosecutors said prison authorities let out inmates so they could kill gang rivals .