The Mexican military was put in charge of security and operations Monday at a major Pacific port in Michoacan, a western state plagued by drug cartel violence. Government security spokesman Eduardo Sanchez said high-ranking navy officers were taking over the administration and captaincy at the port of Lazaro Cardenas, which has the country's largest general cargo volume. The move came one week after armed groups sabotaged government-owned power stations in Michoacan, causing blackouts in an attack that officials suspect was orchestrated by the Knights Templar gang. The federal government deployed thousands of troops to Michoacan in May in an effort to rein in the cartel, whose reign of violence has prompted several towns to form vigilante groups. Sanchez said the military was also taking charge of customs at Lazaro Cardenas. "The military will guarantee commerce and will monitor fiscal obligations," he told a news conference. Troops, meanwhile, replaced the municipal police in the city and the local officers will undergo evaluations to determine if they are fit for the job. More federal police were deployed to roads leading to the port, which has become a destination for chemical precursors used by drug traffickers to produce crystal meth. Elsewhere in Mexico, the mayor of the northeastern city of Matamoros urged residents to stay home due to new gunfights after 13 people were killed in shootouts a day earlier. Mayor Leticia Salazar said carloads of gunmen entered the city again on Monday but she did not say whether there were new victims. The city, which is across from the US city of Brownsville, Texas, has been a battleground between the Gulf and Zetas drug cartel. The clashes involved criminal groups, Salazar said, without specifying if it was infighting within a cartel or battles between the Zetas and Gulf gangs. The 13 who died in three shootouts on Sunday were part of organized crime groups, she said. Two of the gunfights involved the military. Pick-up trucks used by some of the gunmen bore numbers that identify them as members of the Gulf cartel, the mayor said, citing military information. Authorities captured leaders of the Gulf and Zetas cartels this year. More than 77,000 people have died in drug-related violence across Mexico since 2006.