Eight inmates were attacked and killed in a Mexican prison near the U.S. border a day after being transferred to the facility, the local state government said on Thursday.
The killings took place on Wednesday afternoon in Nuevo Laredo, across the border from Laredo, Texas, when several prisoners attacked the newly arrived inmates with home-made knives, the ministry of public security in the northeastern state of Tamaulipas said in a statement.
Violence has engulfed Tamaulipas for several years as drug traffickers have vied for control of border smuggling routes. It was unclear if the prison killings were gang-related.
The eight victims were incarcerated on suspicion of committing various crimes ranging from murder to robbery.
Six inmates have accepted responsibility for the killings, the ministry said.
Mexico's overcrowded prisons have been rocked repeatedly by violence, and drug gangs wield strong influence inside many. In April, 13 people were killed and some 65 injured in a prison riot in the central state of San Luis Potosi.
Roughly 1,000 people have died each month in drug-related murders since President Enrique Pena Nieto took power in December vowing to quell criminal violence.
The government has claimed success in reducing the death toll caused by warring drug gangs, but it is still struggling to control the violence in a number of Mexican states.
Around 70,000 people died in drug-related bloodletting under Pena Nieto's predecessor Felipe Calderon, who sent in the armed forces to tame the cartels soon after assuming office at the end of 2006.