"The situation in Mexico today is significantly different than it was just a decade ago," department Director Steven C. McCraw said in a news release.
"Many crimes against Americans in Mexico go unpunished, and we have a responsibility to inform the public about safety and travel risks and threats. Based on the unpredictable nature of [drug] cartel violence and other criminal elements, we are urging individuals to avoid travel to Mexico at this time."
While the Mexican government has made "great strides battling the cartels," McCraw said, "drug cartel violence and other criminal activity represent a significant safety threat, even in some resort areas."
The DPS cited U.S. State Department statistics that showed 12,903 narcotics-related homicides in Mexico were reported in the first nine months of 2011 and the number of U.S. citizens reported murdered in Mexico increased from 35 in 2007 to 120 in 2011.
The U.S. State Department also reported rapes and sexual assaults continue to be serious problems in resort areas.
U.S. citizens living or traveling in Mexico are urged to register with the nearest U.S. embassy or consulate.