DEL CITY, Okla. (AP) — Police in suburban Oklahoma City say a 13-year-old student who participated in a walkout to protest gun violence now faces a criminal charge after making a threat at his school.

Authorities in Del City say the student told a schoolmate Wednesday not to come to Del Crest Middle School the next day because he planned to "shoot up" the campus.

Two other students overheard the conversation and told school officials. Police say the accused student told the school principal he was joking, but the teen was taken into custody on a complaint of making a terroristic hoax.

Police say they want students to know gun violence is not a joke.

Students throughout the nation walked out of schools Wednesday in memory of 17 killed at a high school in Parkland, Florida.