Police uncovered 13 more bodies in mass graves in northeast Mexico on Friday.
It comes after 59 dead were exhumed in the state of Tamaulipas on Wednesday.
Reports say gunmen pulled passengers from buses headed towards towns near the US border.
A local official said it was believed the bodies were not migrants looking to enter the US but people who refused to be recruited by the Los Zetas drug cartel.
Earlier this week thousands of Mexicans protested in 24 states against the government’s strategy against narcotics crime and the increasing violence in the country.