WASHINGTON (CBSLA.com) — The U.S. State Department issued a new travel warning Tuesday for people planning to visit certain parts of Mexico.

The State Department said U.S. citizens have been the victims of violent crimes – including kidnapping, carjacking, robbery and even homicide in certain Mexican states.

Gun battles between rival gangs or with Mexican authorities have taken place on streets in public places and in broad daylight, the State Department warned.

U.S. citizens have been murdered in carjackings and highway robberies – frequently at night and on isolated roads, the State Department said. U.S. citizens should use toll roads whenever possible, and are warned that there is little or no cellphone service in remote areas.

Kidnappings can take multiple forms – traditional, where a victim is abducted and held for ransom; express, where a victim is abducted for a short time and commonly released after withdrawing money from an ATM; and virtual, where a victim is contacted by phone, coerced into providing the numbers of family and friends, and then isolated until a ransom is paid.

The Mexican government does dedicate substantial resources to protect visitors to major tourist destinations and is fighting drug gangs and other criminal organizations, and there is no evidence that U.S. citizens are being targeted for their nationality, the State Department said.

Resort areas and tourist destinations in Mexico generally do not see drug-related violence and crime seen in border areas and major trafficking routes, the State Department said.

For more information, including a state-by-state breakdown of potentially risky areas in Mexico, click here.