Reports of an active shooter inside Arapahoe High School in Centennial, CO on Dec. 13, 2013 have prompted the lockdown of all Arapahoe, Elizabeth and Aurora schools in Colorado.
Colorado's 9 News reported on Friday that at least two people were injured during a shooting at the school.
UPDATE 4 p.m. ET: 9 News is reporting that the suspect is dead inside the school from a possible self-inflicted gunshot wound.
ABC 7 in Denver tweeted that all Littleton Public Schools are currently on lockdown due to the shooting.
#Breaking: More than 20 police cars at Arapahoe High School, responding to active shooter inside school. 2 shot - @DenverChannel
In addition, schools in Elizabeth, Cherry Hill and Aurora are on lockdown.
Arapahoe County Sheriff Grayson Robinson spoke with ABC 7 and stated that he believes there are "two victims and that the suspect is inside the school."
The identity of the victims have not been released.
There have been several tweets indicating that the gunman has been shot. Authorities have not confirmed this.
ABC 7 is reporting that at least 20 police vehicles are at the school and rescue vehicles are on the scene.
Arapahoe High School is a part of Littleton Public Schools. The school has 2,2229 student in attendance and covers an area of 254,000 square feet. There are 70 classrooms in the school.
The school is in the same county where James Holmes is accused of having killed 12 people in a movie theater in the town of Aurora.
This story is still developing. Follow @DenverChannel on Twitter for the latest updates.