The head of Mexico’s Sinaloa drug cartel has instructed associates to use deadly force north of the border, authorities said.

Joaquin "El Chapo" Guzman, Mexico's most wanted fugitive, has reportedly instructed associates to open fire across the border if necessary against competitors and law enforcement.

Police officers in Arizona have been alerted after Guzman reportedly delivered the message south of the Arizona border in March.

In El Paso police say they continue to be as vigilant as they usually are regardless the warnings.

“As far as law enforcement is concerned we haven't had to change the way we operate. The most important thing is being aware of the information of what is happening and sharing that information with our officers out there,” said Javier Sambrano with the El Paso Police Department.

Sambrano said El Paso has not had any problems like they have seen in Arizona and that Arizona has fewer physical borders like the Rio Grande in El Paso.