LOS ANGELES, Sept. 11 (Xinhua) -- A 16-year-old student opened fire at the Evergreen High School in the Rocky Mountains west of Denver, the U.S. state of Colorado on Wednesday, killing himself and injuring two classmates.

The shooter targeted two students with a handgun before turning the weapon on himself, said Jacki Kelley, a spokesperson for the Jefferson County Sheriff's office.

One of the wounded was in critical condition, while the other suffered non-life-threatening injuries.

Authorities have not yet determined a motive for the shooting but are investigating the shooter's home, locker and social media activities. ■