The mayor of Lazaro Cardenas, a port city on Mexico's Pacific coast, was arrested on kidnapping, extortion and criminal conspiracy charges, officials said.
Arquimides Oseguera was turned over to state prosecutors, the federal commissioner for security and development in Michoacan, Alfredo Castillo, said.
Oseguera is accused of having links to the Caballeros Templarios drug cartel, which has a strong presence in the western state of Michoacan, Castillo said in a press conference.
The mayor was arrested early Monday, the federal commissioner said.
Oseguera was elected in 2012 on the leftist Party of the Democratic Revolution, or PRD, ticket and his term was to end next year.
Omar Alejandro Soto Gil, the treasurer of Lazaro Cardenas, was also arrested as a co-defendant in the case.
Oseguera and Soto Gil are just the latest officials to be arrested in Michoacan.
Jesus Reyna, Michoacan's former government secretary, and Apatzingan Mayor Uriel Chavez were detained earlier.
Officials have suspected for some time that the Caballeros Templarios cartel uses Lazaro Cardenas, one of Mexico's largest Pacific ports, to smuggle drugs and illegally mined minerals.
The federal government took over security at the port on Nov. 4 in response to allegations that port officials were on the payroll of drug traffickers.
The federal government deployed soldiers and police in Michoacan on Jan. 13 in an effort to end the wave of drug-related violence in the state.
Federal security forces killed the Caballeros Templarios cartel's two top leaders, Nazario Moreno Gonzalez and Enrique Plancarte Solis, in February and March, respectively.
Moreno and other members of the Familia Michoacana gang formed the Caballeros Templarios organization after he was reported killed by the government in 2010.
The Caballeros Templarios cartel, which deals in both synthetic and natural drugs, commits murders, stages kidnappings and runs extortion rackets that target business owners and transport companies in Michoacan. EFE