Heads of decapitated victims placed around Mexican city

Five people were decapitated and five others were killed in a spate of violent incidents in the Mexican city of Torrean.

"The five human heads were found in various places" in the city, the official said, noting that the first skull had been found on Friday night and the fifth early on Saturday.

The bodies of the victims, all of whom were linked to organised crime according to the official, have not been found.

Five other men were killed in various acts of violence, the official added. Four of them were gunned down and the fifth was stabbed to death.

Torrean is the largest city in Coahuila state, which borders Texas and has been the scene of constant clashes between drug gangs fighting for control of routes used to smuggle narcotics and immigrants into the United States.

An estimated 50,000 people have been killed in violence linked to Mexico's drug trade since 2006, when President Felipe Calderon launched a crackdown on the criminal gangs blamed for the slaughter.

Meanwhile a Mexican journalist was shot dead by unknown gunmen in a northern municipality of Monterrey, becoming the first reporter to be killed in the country in 2012.

The killing of Raul Quirino Garza, 30, on Friday came one day after the Vienna-based press watchdog IPI named Mexico as the world's deadliest place for journalists to work. Ten journalists were killed in Mexico in 2011.

Quirino Garza, who worked for The Last Word local newspaper, came under fire while driving his car in the Cadereyta municipality, an intelligence official told reporters on condition of anonymity.

Emergency services were called but were unable to save the journalist, the Agencia Estadal de Investigaciones official said. Fifteen bullet casings from high calibre weapons were found at the scene.

According to IPI, a total of 103 journalists were killed in 2011 - the second highest toll on record after 2009, when 110 journalists lost their lives while covering stories.

-AAP