EL PASO, Texas – Officials along the southern U.S. border say they are beefing up security after learning that warring Mexican cartels have approved sending hit men into the United States.

Police and federal agents told The Associated Press about the warnings Monday. Officer Chris Mears of the El Paso police in Texas says authorities learned of the threat last week.

Officials say the cartels have given their hit men permission to cross the border to kill their targets.

Cartel violence has killed thousands of people in Mexico this year. Nearly 800 people have been killed this year in Ciudad Juarez, across the border from El Paso.