A mass shooting on the Las Vegas strip, concert goers sharing their eye witness accounts on social media.

FOX's Carley Shimkus reports:

Twitter flooded with eye witness accounts after police say 64-year-old gunman Stephen Paddock opened fire at a concert in Las Vegas.

Jason Aldean was on stage when Paddock started firing into the crowd...

Aldean reacted on Instagram calling the shooting "beyond horrific." Concert goers also turned to social media with their first hand accounts.

Professional poker player Dan Bilzerian shared a video while fleeing the scene saying he just saw a victim get "shot in the head."

Facebook activated its safety check feature and set up a crisis response page. Police are asking people who have cellphone footage to call 1-800-CALLFBI.

Carley Shimkus, FOX News.

Follow Carley Shimkus on Twitter: @CarleyShimkus