EDINBURG — Authorities in South Texas said today that they won't be intimidated by increasingly violent drug smugglers, announcing a larger Border Patrol presence and that more heavily armed deputies will be authorized to return fire across the Mexican border. Operation "River Freedom Denial" will target areas along the Rio Grande in the southern tip of Texas where violence has risen lately with more ground and air resources, said Border Patrol sector chief Ronald Vitiello. Standing with a Texas Department of Public Safety captain and the Hidalgo County Sheriff, Vitiello cited an exchange of gunfire between his agents and drug...