Violence in Mexico could spill over to the U.S. as an FBI intelligence report said the Mexican gulf cartel may be preparing for possible confrontations with U.S. law officers.

The report says a leader of the cartel's enforcer group, the zetas, ordered dozens of reinforcements to Reynosa, Mexico, across from McAllen which is in south Texas.

The FBI declined comment on the report, but an FBI spokesman did say the Zetas are a significant problem in Mexico and have the potential to pose a significant problem to law enforcement on this side of the border.