Firefighters have found six bodies inside a burning car in Tijuana, and 10 people were killed in two separate shootings in another northern Mexican border town besieged by drug violence.
Near Mexico's southern border, meanwhile, the bullet-ridden bodies of eight men suspected to be drug traffickers were found in a Guatemalan frontier town.
In Tijuana, across the border from San Diego, four bodies were found in a burning compact car's seats and two in the trunk, according to a police report Tuesday.
The victims' identities and the motive for killings were not released, but the Mexican city is on a major route for drugs heading north and has recently seen a wave of violence between warring gangs. The bodies were found Monday night.
In Ciudad Juarez, gunmen opened fire inside a hardware store, killing the woman who owned the store and four other people, including a 19-year-old man, the regional attorney general's office said. Minutes later, an armed gang killed five men riding in a pickup truck.
Ciudad Juarez, across from El Paso, Texas, is Mexico's deadliest city with more than 1,300 killings so far this year. The city is in the midst of an intense turf battle between the Juarez and Sinaloa cartels.
Officials held a ceremony for 1,200 Mexican army soldiers who were being withdrawn from Ciudad Juarez. The troops were part of a contingent sent there earlier this year to fight crime while the city trained more police officers.
The military has trained 1,027 police officers for the city, which now has a police force of 3,025 officers, about a third larger than its previous size.
President Felipe Calderon has deployed more than 45,000 troops to drug hotspots since taking office in 2006. Drug violence has since surged, claiming more than 13,500 lives across Mexico.
The bodies in Guatemala were found in the San Marcos region, which has become a major transit point for cocaine shipments that often are left at sea to be picked up by local traffickers and smuggled into Mexico.
Police spokesman Juan Choguix said the eight men were suspected of being drug smugglers.
Guatemala has been increasingly plagued by drug violence mirroring Mexico's gang wars. Guatemalan President Alvaro Colom has blamed the drug trade for many the 6,200 homicides that occurred in the Central American country last year.
In Mexico's northern state of Zacatecas, which has seen the increasing presence of the Gulf Cartel in recent years, a convoy of gunmen opened fire on two government vehicles that were heading to
an event to pick up state Gov. Amalia Garcia, her office said in a statement.
The governor was not in the vehicles, and it was not clear if she was the target. The government blamed organized crime for the attack.
Zacatecas is a largely rural state that has seen a rise in cartel activity. On May 16, 53 inmates escaped from a prison with the alleged complicity of guards. The Zetas, a gang of hit men tied to the Gulf cartel, supposedly participated in that jail break.
In the northern city of Hermosillo, the federal police announced the capture of Ignacio Paez, accused of controlling a drug trafficking corridor in Sonora state and charging migrant smugglers for traveling through the area.