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.

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

Two teenagers are under arrest for allegedly plotting "a mass casualty attack" at a Houston-area high school, the FBI said Wednesday night. The teen girls were accused of threatening to place pipe bombs and shoot their peers,