DALLAS (AP) - A suburban Dallas teenager has pleaded guilty to plotting an Islamic State group-inspired mass shooting at North Texas mall.

Prosecutors say Matin Azizi-Yarand pleaded guilty Monday in state court to solicitation of capital murder and making a terroristic threat. The 18-year-old was sentenced to 20 years in prison.

Azizi-Yarand was arrested last May and indicted in July . Authorities allege the then-high school student spent more than $1,400 buying weapons and tactical gear, and had been trying to recruit others to help him in the shooting.

U.S. Attorney for the Eastern District of Texas Joseph Brown says it's "extremely rare" for someone to be prosecuted on terrorism charges in state court.

Azizi-Yarand was being held in the Collin County jail Monday afternoon. His attorney could not immediately be reached for comment.

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