A prisoner was taken away by police during a riot at La Mesa jail in Tijuana in Mexico's state of Baja California September 17, 2008. At least nineteen people have been killed and some 12 others injured after the riot, officials said Thursday. [Xinhua/Reuters Photo]

At least 19 prisoners were killed in a riot at the La Mesa State Penitentiary in the border city of Tijuana in northwest Mexico after police opened fire to regain control of the facility, authorities said Thursday.

Forty-three people were injured during the melee, officials said.

The General Prosecutor of Justice (PGJ) Office from Mexico's Baja California state said 19 bodies were found after Wednesday's riot, the second in three days, was brought under control.

Tijuana's authorities said all the bodies of prisoners bore signs that they were killed in a violent way.

The first riot erupted on Sunday night after an officer and two guards killed a prisoner. Police took control during the first hours of Monday with at least three people dead and 31 others injured.

Chaos continued on Tuesday and Wednesday as relatives demanded information about their loved ones. Four hours into Wednesday's riot, authorities retook control of the situation.

According to local radio reports, the state government decided to send troops of the Preventive Federal Police (PFP, military police) to take control of the prison.