Authorities charged a 13-year-old boy with murder Saturday after a fatal shooting of a classmate at a middle school in the U.S. state of New Mexico.

Police said the boy shot another 13-year-old boy during their lunch break on the third day of the fall term at the school in Albuquerque. Six shots were fired.

Officials called the victim a "hero" who was killed while trying to de-escalate a confrontation between two other students. The accused shooter brought the gun from home, police said. The school will be closed Monday. New Mexico’s governor promised to address the “scourge of gun violence.” 

A group that advocates for gun restrictions says there have been at least 43 incidents of gun violence in U.S. schools this year, resulting in 12 deaths.

Friday’s gunfire came just hours after a shooting at an Albuquerque nightspot left one person dead and three injured, and puts the city on pace to shatter its homicide record for the year.

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