MEXICO CITY (AP) — Another inmate was killed Thursday at a prison in northern Mexico where 16 inmates died during a riot on New Year's Eve.

Security officials in Zacatecas state said a new riot broke out at the Cieneguillas prison, where 16 prisoners died on Tuesday.

The Public Safety Department said the prison had been brought back under control, but there was no information on how the inmate was killed.

Following Tuesday's riot, authorities confiscated four guns that they believe were smuggled in during visiting hours. Prison guards were placed under investigation after the riot.

Not all of the victims in Tuesday's riot died from gunshot wounds. Some were stabbed and others beaten with objects. No guards or police were wounded.

Local media reported the prison held members of various gangs and cartels, including the Sinaloa cartel and the Gulf and Northeast cartels.

Such killings frequently involve score settling between rival cartel members or a battle for control of the prison's illicit business.

Mexico has a long history of deadly prison clashes. In October, six inmates were killed in a prison in Morelos state.

In September, Nuevo Leon state closed the infamous Topo Chico prison, the site of many murders over the years. In February 2016, 49 prisoners died there during rioting when two factions of the Zetas cartel clashed.