Chihuahua , specifically Ciudad Juarez , is of special concern , '' the alert says . `` Mexican authorities report that more than 2,600 people were killed in Ciudad Juarez in 2009 , '' the report states . `` Additionally , this city of 1.3 million people experienced more than 16,000 car thefts and 1,900 carjackings in 2009 . U.S. citizens should pay close attention to their surroundings while traveling in Ciudad Juarez , avoid isolated locations during late night and early morning hours , and remain alert to news reports . '' But the problems are not limited to Juarez , the State Department says . `` Mexican drug cartels are engaged in violent conflict -- both among themselves and with Mexican security services -- for control of narcotics trafficking routes along the U.S.-Mexico border , '' the report says . `` In order to combat violence , the government of Mexico has deployed military troops throughout the country . U.S. citizens should cooperate fully with official checkpoints when traveling on Mexican highways . `` Some recent Mexican army and police confrontations with drug cartels have resembled small-unit combat , with cartels employing automatic weapons and grenades . Large
Washington -LRB- CNN -RRB- -- The United States has renewed a travel alert to Mexico , citing increased violence in the country . The alert , issued Sunday by the State Department , is in effect until August 20 and supersedes an alert issued August 20 , 2009 . `` Recent violent attacks have caused the U.S. Embassy to urge U.S. citizens to delay unnecessary travel to parts of Michoacan , Durango , Coahuila and Chihuahua ... and to advise U.S. citizens residing or traveling in those areas to exercise extreme caution , '' the alert says . `` Drug cartels and associated criminal elements have retaliated violently against individuals who speak out against them or whom they otherwise view as a threat to their organization . These attacks include the abduction and murder of two resident U.S. citizens in Chihuahua . '' More than 16,000 people have died in Mexico since President Felipe Calderon declared war on the drug cartels shortly after assuming office in December 2006 . Ciudad Juarez , in Chihuahua state across the border from El Paso , Texas , is the most violent city in the nation . `` The situation in the state of