( CNN ) -- The Texas Department of Public Safety took the unprecedented step Thursday of telling college students not to visit Mexican border cities during spring break because they are just too dangerous . Several universities issued similar warnings last year , but this was the first time the Texas law enforcement agency had issued the specific advisory against travel , said spokeswoman Tela Mange . In the past , she said , Texas authorities had just urged students to be careful . `` Because of the increased violence , we decided to step it up a little bit and say , 'Parents , bad idea , ' '' Mange said . DPS Director Steven C. McCraw said , `` Parents should not allow their children to visit these Mexican cities because their safety can not be guaranteed . '' The State Department renewed a travel alert to Mexico last month , citing increased violence in the country -- border areas in particular . `` 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 . 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 Chihuahua , specifically Ciudad Juarez , is of special concern , '' the alert says . Two U.S. citizens were abducted and killed in Chihuahua , the State Department said . `` 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 firefights have taken place in towns and cities across Mexico , but occur mostly in northern Mexico , including Ciudad Juarez , Tijuana , Chihuahua City , Nogales , Matamoros , Reynosa and Monterrey . During some of these incidents , U.S. citizens have been trapped and temporarily prevented from leaving the area . '' A number of areas along the border continue to experience a rapid growth in crime , with robberies , homicides , petty thefts and carjackings increasing during the past year nationwide , the alert says . The State Department reports notable spikes in Chihuahua , Sinaloa , and northern Baja California . `` Ciudad Juarez , Tijuana and Nogales are among the cities which have experienced public shootouts during daylight hours in shopping centers and other public venues , '' the alert says . CNN 's Arthur Brice contributed to this report .
Texas Department of Public Safety : Mexican border cities a ` ` bad idea '' for spring break . It is the agency 's first specific advisory against travel , spokeswoman says . State Department issued a travel advisory to Mexico last month . It noted a rapid growth in violent crimes in areas along the U.S.-Mexico border .