SAN DIEGO (KGTV) - The U.S. State Department issued a travel warning Tuesday for popular Mexico tourist destinations due to criminal activity.

U.S. citizens have been the victims of violent crimes including homicide, kidnapping, carjacking and robbery, State Department officials said in issuing the warning.

Officials urged U.S. citizens to use caution when visiting popular areas such as Tijuana, Rosarito, Ensenada, Tecate, Riviera Nayarit and Mexicali. CLICK HERE to view the full list.

The travel warning explains that U.S. citizens had been murdered in carjackings and highway robberies, most frequently at night and on isolated roads.

Carjackers used various techniques including roadblocks, bumping or moving vehicles to force them to stop, or running vehicles off the road at high speed, officials said.

The State Department warned that criminals target newer and larger vehicles, but drivers of old sedans and buses coming from the United States are also targeted.

Officials added gun battles between rival criminal groups or with Mexican authorities have taken place on streets and in public places during broad daylight, officials said.

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Officials said: "U.S. government personnel and their families are prohibited from personal travel to all areas to which the Department recommends 'defer non-essential travel' in this Travel Warning. As a result of security precautions that U.S. government personnel must take while traveling to parts of Mexico, our response time to emergencies involving U.S. citizens may be hampered or delayed."

U.S. government personnel are also not permitted to drive from the international border to Mexico's interior. Personnel are also banned from intercity travel after dark in many areas of Mexico.

The State Department detailed security conditions for states in Mexico, specifically highlighting the areas in which U.S. government personnel and U.S. citizens should "defer non-essential travel." CLICK HERE for a State-by-State Assessment

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In some places, criminal organizations have created their own checkpoints staffed with people in unauthorized police and military uniforms, said the State Department.

There is no sign U.S. citizens are being targeted, officials said.