MEXICO CITY - Some 14 people died in a series of lasting five hours in northeastern Mexico, official confirmed in the early hours of Monday.
The clashes occured the day before in the towns of Madero and Tampico, an area where the Gulf Cartel and the criminal gang Los Zetas are active, authorities in the state of Tamaulipas said.
The clashes started in Madero when unidentified attackers killed two men and one woman.
A further 11 people were killed in six different sites in Madero and Tampico.
The authorities did not say which organizations were suspected of carrying out the killings.