Ariana Grande spoke out hours after an explosion following her concert Monday night killed at least 22 people and injured many others.

“Broken,” the pop star tweeted… “From the bottom of my heart, i am so so sorry. i don’t have words.”

A deadly explosion outside the Manchester venue where Grande was performing, is believed to be the work of a suicide bomber. Grande, who was just finishing her performance when the explosions happened around 10:35 p.m. local time, was not injured.