A soldier watches over seized packages of marihuana during a presentation of the 2nd military zone achievements to the media in Tijuana, Mexico, on Nov. 3, 2012. Mexican Army seized over 2 tons of marihuana during a security operation held on Friday. (Xinhua/Guillermo Arias)

Soldiers watch over seized packages of marihuana during a presentation of the 2nd military zone achievements to the media in Tijuana, Mexico, on Nov. 3, 2012. Mexican Army seized over 2 tons of marihuana during a security operation held on Friday. (Xinhua/Guillermo Arias)

A soldier watches over seized packages of marihuana during a presentation of the 2nd military zone achievements to the media in Tijuana, Mexico, on Nov. 3, 2012. Mexican Army seized over 2 tons of marihuana during a security operation held on Friday. (Xinhua/Guillermo Arias)