GRAPHIC: Harrowing video shows students cowering as gunshots ring out

WARNING: The video above contains audible gunshots. Some may find it disturbing.

PARKLAND, Fla. -- During a fatal shooting rampage at a Florida high school, students sought shelter however possible.

Horrifying video obtained by ABC News shows students hiding on the floor beneath desks at Marjory Stoneman Douglas High School. They begin to scream in horror as audible gunshots ring out around them.

Student Matt Walker posted the video to Snapchat with the caption "Our [expletive] school is getting shot up."