The July 4th warning states that there is the potential for confrontations between criminal organizations and Mexican security forces in Baja California, following the July 2 arrest of a prominent cartel leader.

"U.S. citizens should expect to encounter increased Mexican law enforcement presence in those areas. Criminal organization assassinations and territorial disputes can result in bystanders being injured or killed," the travel advisory stated.

The Department of State's Travel Advisory for Baja California has been raised to Level 3 and U.S. tourists are being told to reconsider travel due to crime and kidnappings.

Travel warnings by the U.S. for Tijuana are common.  In March the state department issued a warning about crime and kidnappings.  It warned that "travelers should remain on main highways and avoid remote locations … of particular concern is the high number of homicides in the non-tourist areas of Tijuana."