Inmates took a guard hostage as clashes broke out early Sunday morning at a prison in Apodaca, Nuevo Leon, said state security spokesman Jorge Domene.

He did not rule out the possibility the melee masked an escape. Guards could have been complicit and they, along with the prison’s director, have been detained for questioning, he said.

Some prisoners also set mattresses ablaze, Domene said, sending a column of smoke rising above the facility.

Federal and state police had the situation under control later in the day.

The clashes, which occurred in a part of the prison where most inmates were serving time for federal drug trafficking offenses, may have begun as a fight between the Zetas and Gulf cartels, Domene said.

The Zetas started with deserters from the Mexican Army, and quickly gained a reputation for ruthless violence as the armed branch of Mexico’s Gulf cartel. It split off into a separate drug-trafficking organization in 2010.

Friends and family members of inmates gathered outside the prison to find out whether their loved ones had died.

In May 2011, 14 inmates were killed and 35 people were injured in a fire in the prison’s psychiatric ward.