The Associated Press reports that 26 people, including at least 18 children, were killed in the Friday morning shooting at Sandy Hook Elementary School in Newtown, Conn. The gunman, identified as a man in his twenties whose mother reportedly worked at the school, was also killed.
"Our hearts are broken today," President Barack Obama said at a Friday afternoon press conference.
Celebrities, journalists, politicians and many others have taken to Twitter with reactions to the horrific tragedy. Many have offered condolences to the Newtown community, expressing shock, sadness and great concern; while others, such as filmmaker Michael Moore and CNN host Piers Morgan, have questioned the need for stricter gun control laws in the face of catastrophes like this one.
"All our words seem so small, so meaningless in the face of such horror," tweeted Anderson Cooper on Friday afternoon.
Click through this slideshow to see more celebrity Twitter reactions to the Sandy Hook tragedy: