MEXICO CITY - At least 12 people were killed on Thursday in three mass murder cases in southern Mexico, the authorities said.

In the first case, unidentified men shot dead five people and injured another in a bar in the municipality of Atoyac de Alvarez, local police said in a statement.

In the second case, the body of a man between 25 and 30 years old was found by the police in the tourist resort of Acapulco.

In the third case, six bodies were found on a highway in the city of Chilpancingo, capital of Guerrero state. The bodies had several gunshot wounds with their faces covered and hands tied behind, which indicated that they had been tortured.

More than 41,279 people have been killed across Mexico since the federal government launched a crackdown in December 2006 against organized crime, especially drug cartels, according to local press.