Mexican authorities say the bodies of two of nine police officers kidnapped by gunmen on Friday have been found.
The director of the Guerrero State Investigative Police says the Mexican army is helping police search for the other missing officers.
The nine officers were seized by an unknown gang after they had gone to identify and recover a body in a northern part of the southern state of Guerrero on Friday.
Several drug gangs are battling for control of smuggling routes in the state.
In another part of Guerrero, state police say unidentified men traveling in two vehicles threw two human heads into a refreshment stand. One of the heads was blindfolded with duct tape.
In northeastern Mexico, the Mexican Defense Department says troops killed three suspected drug cartel gunmen in a gunbattle and also freed a kidnap victim near Monterrey.
Fernando Monreal Leyva, director of the State Investigative Police, said one of his agency's commanders and a team of eight agents had gone to identify and recover a body in a northern part of the state Friday. He said contact was lost with the group that afternoon, and officials learned the officers had been seized by an unknown gang of gunmen. Several drug gangs are battling for control of smuggling routes in Guerrero state.
Monreal said the incident was not connected to the kidnapping of his officers.
In northeastern Mexico, troops killed three suspected drug cartel gunmen in a gunbattle and also freed a kidnap victim near the industrial city of Monterrey, the Defense Department said Saturday.
A military statement said soldiers responding to an anonymous tip in the town of Mina, in Nuevo Leon state, were fired on by three gunmen travelling in an SUV with Texas license plates Friday afternoon. The three attackers were killed, and troops recovered three rifles, two grenades, 475 bullets and four military-style uniforms, the army said.
Later Friday, soldiers came across an SUV that had crashed against the wall of a bridge in the town of Sabinas Hidalgo, also in Nuevo Leon, the press release continued.
Soldiers found a man with a bulletproof jacket inside the vehicle, along with an AK-47 rifle and three ammunition clips. The man allegedly refused to identify himself and was detained. Another person in the car was believed to have been kidnapped and was released by the troops.
Nuevo Leon has seen a surge in drug violence since the Zetas gang split with its former employer, the Gulf cartel.
Across Mexico, drug-gang violence has claimed more than 28,000 lives since December 2006, when President Felipe Calderon took office and deployed thousands of troops and federal police to crack down on the cartels.