1 LINKEDIN 1 COMMENTMORE

LITTLETON, Colo. (AP) - The Jefferson County Sheriff's Office says Columbine High School, the scene of a school shooting that left 15 people dead in 1999, is on a high security alert after an undisclosed threat.

The sheriff's office says in a tweet that the school is on lockout, which does not require students to take shelter, after authorities were notified of a telephone threat. The alert also applies to a half-dozen other schools in the area and was issued shortly before noon.

In 1999, two students opened fire at Columbine High School in Littleton, Colo., killing 12 classmates and a teacher and wounding 26 others before killing themselves in the school's library.

(Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)

Read or Share this story: http://on.ksdk.com/1jFwk47