The U.S. counsel in Veracruz, Mexico reminded Americans to be careful in the state after a Texas woman and her two kids were killed in an attack on a bus. Maria Sanchez Hernandez and her daughters, Karla,19, and Cristina, 13, were among seven passengers slain last week when a gang of gunman boarded three buses traveling between the towns of Tempoal and Panuco. "American citizens residing in, visiting or traveling through the northern portion of Veracruz that borders Tamaulipas and San Luis Potosi should maintain a heightened sense of alert," the consulate said in a written statement. The three Americans lived in Fort Worth and held dual U.S. and Mexican citizenship, CNN said.