The Mexican army has ordered three junior officers and 10 soldiers to stand trial on drug trafficking and organized crime charges after they were allegedly caught with more than a ton of methamphetamines and 66 pounds (30 kilograms) of cocaine.
The soldiers were arrested last week with drugs at a military checkpoint south of Tijuana, across the border from San Diego. They are being charged within the military justice system.
The Defense Department said in a statement it will "in no way tolerate" such acts.
Corruption is widespread among Mexican police, and some experts worry it could spread to the tens of thousands of soldiers assigned to fight drug traffickers across the country.
In the Pacific coast resort of Acapulco, police on Friday found the dismembered body of a man near the city's main coastal boulevard. A police statement said a car was set afire beside the body, and two handwritten signs were also found nearby.
"Here is your garbage," read one. Such signs are frequently left by drug gangs to threaten rivals and authorities.
Outside Acapulco, on the toll road to Mexico City, a man's bound, mutilated body was found near a burned-out car. The unknown victim had been shot in the face and head, and his ear was severed, according to police in Guerrero state, where Acapulco is located.
Another body that had been cut in pieces was found in three plastic bags dumped on a street in a residential area of Acapulco, police said.
Near the city's colonial San Diego Fort, meanwhile, unidentified assailants attacked three homes with gasoline bombs, gunshots and a grenade that failed to explode. No injuries were reported in those attacks.
In the northern state of Coahuila, across from Texas, a state trooper, a female passer-by and five gunmen were killed during a series of shootouts between police and presumed cartel henchmen, authorities said.
Gunmen in three sport utility vehicles attacked police in state capital, Saltillo, on Friday morning, leading to a chase and gunfight that killed two attackers and injured four officers, the Coahuila state prosecutor's office said in a statement.
Minutes later, gunmen riding in SUVs ambushed and killed a state police officer in nearby Ramos Arizpe. An hour later in Saltillo, three gunmen and a woman who was caught in the crossfire died in another shootout between police and suspected traffickers.
Prosecutors didn't say whether the three incidents were related.
Saltillo, a city of about 750,000 people near the industrial hub of Monterrey, and the surrounding area had largely avoided the worst of a wave of violence in northeastern Mexico arising from a turf fight between the Gulf drug cartel and its former hit men, the Zetas.
Associated Press writers Sergio Flores in Acapulco and Mark Walsh in Monterrey contributed to this report.