Texas authorities are warning Americans to stay away from the Mexican border town of Nuevo Laredo over the Fourth of July holiday weekend because of a possible surge in drug gang violence.

The Texas Department of Public Safety says it has credible information that the Zeta drug cartel is planning to target U.S. visitors for robberies, extortion and car theft.

Nuevo Laredo is just across the border from the Texas city of Laredo and is a popular tourist spot.

The Zetas are a notoriously violent drug gang, known for using heavy weapons in its battle with other gangs for domination of the northern Mexican drug trade.

Mexican President Felipe Calderon has deployed the army to the region to try to stop the violence, which has killed thousands, including civilians.