Four police officers were among nearly two dozen people killed after security forces engaged in an hour-long gunbattle with suspected cartel members Saturday in a Mexican town near the U.S. border, days after President Trump said he was moving to designate Mexican drug cartels as terror organizations. The shootout happened around noon in the small town of Villa Union, a town in Coahuila state located about an hour’s drive southwest of Eagle Pass, Texas. Coahuila state Gov. Miguel Angel Riquelme told local media that four of the dead were police officers killed in the initial confrontation and that several municipal...