Mexico's brutal Zetas drug cartel expands south unchallenged

IXTEPEC, Mexico This is not northern Mexico, where drug gangs fight for turf along the U.S. border and the Mexican government wages an open battle against them. This is the south, where the brutal Zetas cartel is quietly spreading a reign of terror virtually unchallenged, all the way to the border with Guatemala -- and across it.

Just as they have done in the north, groups claiming to be Zetas have set up criminal networks to control transit routes for drugs, migrants and contraband such as pirated DVDS, intimidating the populace and committing gruesome murders as an example to the uncooperative.

Four years ago they started preying on the south, Mexico's poorest region. They moved into Oaxaca, Chiapas and other southern states and then northern Guatemala, where attacks on townspeople became so commonplace that the government last month sent in 300 troops to regain control of the border province of Alta Verapaz.

In towns on the Oaxacan isthmus and the center of Oaxaca city, the capital, the wealthy as well as street vendors and migrants have been kidnapped and subjected to extortion.