Los Chapos, members of the notorious Sinaloa cartel formerly led by Joaquin “El Chapo” Guzman, and the local group Los Mexicles clashed at a prison on Thursday afternoon, Deputy Security Secretary Ricardo Mejia said. A riot then broke out, leaving two dead and four wounded with bullet wounds, Mejia said, speaking alongside Mexican President Andres Manuel Lopez Obrador at a regular news conference. Another 16 were injured in the fighting, he said. Sign up now for FREE unlimited access to Reuters.com Register Officials did not say what caused the collision. After the uprising, the Mexiclos stormed the city, authorities said, killing nine civilians. Among them were four employees of a radio station, including an announcer, Mejia said. Across the city, department stores were shot at and set on fire. FEMSA, the parent company of the Oxxo chain, said in a statement that one of its employees and a woman applying for a job were killed in the violence. Around 1 a.m. Friday, six alleged Mexicles members were arrested by local police, with the help of the Army and National Guard, Mejia said. By Friday afternoon, about 300 army troops were scheduled to arrive in the city, with another 300 to follow. “Mayor (Juarez) Cruz Perez informed us that (the city) is now in a state of calm; public order has been restored,” Mejia said. “We hope it doesn’t happen again, because innocent people were attacked,” López Obrador said. Thursday’s attacks followed clashes between cartels and the military in central Mexico, which saw taxis, buses and about 20 Oxxo stores torched, Lopez Obrador said. read more “We should not and cannot get used to these kinds of events,” said retail group ANTAD. “Mexico doesn’t deserve it.” Sign up now for FREE unlimited access to Reuters.com Register Report by Kylie Madry. Additional reporting by Tomas Bravo. Edited by Ross Russell and Alex Richardson Our Standards: The Thomson Reuters Trust Principles.