MEXICO CITY (AP) — The governor of the central Mexico state of Zacatecas said Friday the director of a state prison where 17 inmates were killed this week will be relieved of his position.

Gov. Alejandro Tello said in a news conference that he was not denigrating the efforts of the prison director, but said the incidents made a change necessary.

Sixteen inmates were killed in a riot Tuesday at the Cieneguillas prison. Another inmate was killed Thursday. Authorities confiscated four guns after Tuesday’s melee.

Tello described the prison as a “time bomb” in an interview Friday with the state television station. Five different cartels are present among a population of more than 1,120 inmates and conflicts outside between the groups have a tendency to manifest inside as well, he said.

Mexico’s National Human Rights Commission condemned the prison murders Friday and demanded a thorough investigation.