Seth "Andrea" Gregori, 21, is charged with two misdemeanors after allegedly planning an attack on police similar to the 2016 Dallas ambush.

Local and federal authorities are saying they thwarted a mass casualty attack Monday morning with the arrest of a 21-year-old Texas man accused of making terrorist threats against police officers.

A South Texas resident was arrested Monday after authorities say the 21-year-old threatened local police and was plotting an attack reminiscent of the deadly 2016 Dallas police ambush, officials said.

A Texas measles outbreak has doubled in the last week to 124 cases, state health officials said Tuesday, a day after they warned a person infected with the highly contagious disease had traveled from the outbreak zone.

The measles outbreak in rural West Texas has grown to 124 cases across nine counties, the state health department said Tuesday, and 18 people are hospitalized. The outbreak is largely spreading in the Mennonite community in an area where small towns are separated by vast stretches of oil rig-dotted open land but connected due to people traveling between towns for work,