A wave of drug-related violence claimed the lives of 17 people in Nuevo Leon state and four others in Coahuila state, both located in northern Mexico, officials said.
Military personnel found the bodies of three adults and a minor at a car wash in Saltillo, the capital of Coahuila.
The victims, who were gunned down, were found in Postal Cerritos, a neighborhood on the east side of Saltillo, the Coahuila Public Safety Secretariat said.
Three men, ranging in age from 18 to 25, were kidnapped and murdered in Santa Catarina, a city in Nuevo Leon state, police said.
Mexican drug cartels often kidnap people and later kill them, with no ransom ever demanded.
Two bodies were discovered inside an SUV at kilometer 24 of the Libramiento Noreste highway in the city of Escobedo.
Gunmen killed a woman outside her house in Escobedo, the Nuevo Leon State Investigations Agency, or AEI, said.
The mutilated body of a man, meanwhile, was found in Cienega de Flores, a city north of Monterrey, the capital of Nuevo Leon, the AEI said.
Two dismembered bodies were discovered in Pesqueria, a city in central Nuevo Leon, the AEI said.
Two men were killed and a woman was wounded by gunmen in Montemorelos, a city in the southern part of Nuevo Leon, officials said.
Two people were murdered in another drug-related incident in the city of Apodaca.
Gunmen traveling in several vehicles killed three men and a woman in Monterrey's Alfonso Reyes district on Wednesday afternoon, an AEI spokesman said.
The Gulf cartel and its former armed wing, Los Zetas, have been battling for control of Nuevo Leon and Coahuila.
Heriberto Lazcano Lazcano, known as "El Lazca," deserted from the Mexican army in 1999 and formed Los Zetas with three other soldiers, all members of an elite special operations unit, becoming the armed wing of the Gulf drug cartel.
After several years on the payroll of the Gulf cartel, Los Zetas, considered Mexico's most violent criminal organization, went into the drug business on their own account and now control several lucrative territories.
The violence has spiked this month in Mexico, with the Mexico City daily Reforma reporting recently that the death toll for this year stands at more than 6,300.
More than 50,000 people, according to official figures, have died in drug-related violence in Mexico since late 2006, when President Felipe Calderon took office and declared war on the country's powerful drug cartels.
Calderon has deployed tens of thousands of soldiers and Federal Police officers across the country to combat drug cartels and other criminal organizations.
The use of the armed forces to fight drug traffickers, however, has failed to stem the violence.
Mexico registered 27,199 murders in 2011, or 24 per 100,000 people, the highest number since Calderon took office, the National Institute of Statistics and Geography, or INEGI, said in a report released earlier this month.
The Movement for Peace with Justice and Dignity, which was founded by human rights activist and poet Javier Sicilia, puts the death toll from Mexico's drug war at 70,000. EFE