A student at a Colorado high school shot at least one other student on Friday, and then shot and killed himself inside the school.

One of the two victims is in serious condition with a gunshot wound. Another student was wounded but it's unclear if that resulted from a gunshot, Arapahoe County Sheriff Grayson Robinson said at a press conference. 

The shooter was found dead inside Arapahoe High School. He was down within 14 minutes of the first phone call to emergency services. He was a student at the school, Robinson said, but police officials are withholding his name.

“The most important message right now is that the shooter is dead as the result of a self-inflicted gunshot wound so there are no other threats at this time,” Robinson said.

The shooter appeared to be targeting a teacher, he said. The teacher was removed from the school after receiving word of the threat.

Law enforcement officials are not ruling out other possible suspects at this time as a precaution.

SWAT teams appeared at the scene and evacuated students who were inside the school at the time.

Arapahoe is part of the Littleton School District, whose other schools were placed on lockdown Friday.

The high school is located only about 10 miles away from Columbine High School, where more than a dozen people were shot and killed in a mass shooting in 1999. It's also not far from the movie theater in Aurora, Colo., where a dozen people were shot and killed, and nearly 60 were injured, during a mass shooting in July 2012.

The Arapahoe shooting comes a day before the first anniversary of the mass shooting in Newtown, Conn., that left 20 children and six school employees dead at Sandy Hook Elementary School.

Connecticut Sen. Chris MurphyChristopher (Chris) Scott MurphyOvernight Health Care — Presented by the Association of American Medical Colleges — Governors criticize Trump move on pre-existing conditions Bipartisan group of senators asks FDA to examine drug shortages Trump faces Father’s Day pleas to end separations of migrant families MORE (D) reacted to the Colorado shooting in a tweet Friday.

-- Mario Trujillo contributed. This story was first posted at 4:18 p.m., and updated at 4:36 p.m.