MEXICO CITY -- Mexico's new government announced Monday that it was sending more than 6,500 soldiers, marines and federal police to the western state of Michoacan to crack down on a wave of execution-style killings and beheadings that have left hundreds dead.
The operation is the first major offensive against drug gangs by President Felipe Calderon, who was sworn in on Dec. 1 after narrowly winning election on a law-and-order platform.
"The battle against organized crime has just begun," said Interior Secretary Francisco Ramirez Acuna, flanked by the attorney general and heads of the army, navy and federal police.
Federal investigators say the violence in Michoacan, Calderon's home state, stems from a turf war between a local gang called Los Valencia and the northern Mexico Gulf cartel, whose bloody enforcers are known as the Zetas, a group of ex-Mexican army operatives turned hit men.
About half of Michoacan's more than 500 killings this year are linked to the turf war, investigators say.
In apparent attempts to terrorize those who oppose them, the gangs have carried out a wave of decapitations, placing the severed heads on public display with threatening notes including one that read, "See. Hear. Shut Up. If you want to stay alive."
In the most gruesome case, gunmen burst into a nightclub and rolled five heads onto the dance floor. In another, a pair of heads were planted in front of a car dealership in Zitacuaro, a town best known until now as a nesting ground for monarch butterflies.
Security officials said police and soldiers will arrest drug traffickers, mount checkpoints and burn crops of marijuana and opium poppies grown in Michoacan's rugged mountains.
Naval ships also will seal off the state's small Pacific coast, along which smugglers carry drugs on their way north to the United States.