The United Nations' top human rights official called on the Mexican government to set a timetable for withdrawing military personnel from law enforcement duties.

U.N. high commissioner for human rights Zeid Raad al-Hussein said the government should return the soldiers to their barracks.

The Mexican army and marines are leading the fight against the country's drug cartels. But soldiers have been accused of human rights abuses, including a 2014 case in which three soldiers were charged with homicide in the slaying of at least eight suspects after they surrendered.

Zeid said armies weren't designed for police work.

He also called on the government to abide by the recommendation made by an Inter-American human rights commission group for re-examining the case of 43 missing students.