Two teenage girls accused of planning a "mass casualty attack" at a Houston-area high school were arrested, authorities said. The girls, 15 and 16, were taken into custody on Tuesday. Their names were not released by authorities because they are minors.

Evidence suggests their intent was to carry out acts of violence at a school in the Spring Branch Independent School District, law enforcement said.

Two teenagers are under arrest for allegedly plotting what the FBI is calling "a mass casualty attack" at a Houston-area high school.