The "Break Free" singer took to Twitter to write a heartfelt message to fans.
"broken. from the bottom of my heart, i am so so sorry. i don't have words." She wrote.
TMZ reported that Ari is "in hysterics" after learning of the fatal explosion.
She is said to be "devastated that young people who came for a good time are now lying dead and injured" and is "in no condition to perform".
Thoughts are with the victims and their families.