ACAPULCO, Mexico (Reuters) - A human rights group on Thursday slammed an armed vigilante group’ training of children to use guns in a violent region of Mexico after images of the armed minors sparked widespread consternation.

The video footage and photos of small children bearing rifles in the southwestern state of Guerrero were the latest shock to a country that has become increasingly accustomed to troubling news after two years of record levels of violence.

The images, which showed around 20 children doing military style drills, emerged days after 10 local musicians were murdered by suspected cartel hitmen in Chilapa de Alvarez, one of the most violent municipalities in Guerrero, one of Mexico’s most violent states.

Bernardino Sanchez Luna, a leader of so-called community police in the town, said the ongoing failure of federal security forces to protect the area had led residents to instead arm themselves, including local children.

Ramon Navarrete, head of Guerrero’s state human rights commission, urged vigilante groups to desist from using children in such local community policing initiatives.

“We thoroughly reject the involvement of minors in security operations which puts at risk their development, their physical safety and their lives,” the rights commission said in a statement issued by the Guerrero state government.

Guerrero permits indigenous towns to form their own police according to traditional customs. In recent years such groups have flourished, along with other armed self-defense forces as rural communities seek alternatives to often corrupt state security forces, or to stand up to drug cartels.

Such self-defense groups enjoy uneasy relations with state authorities. Some have been effective in reducing the power of organized crime in some areas. However, critics say they often serve as a front for rival criminal interests.

President Andres Manuel Lopez Obrador referred indirectly to the children during a regular news conference on Thursday, saying some security experts believed that the arming of minors showed armed groups were running out of adult recruits.