Chris Evans and rockers Nikki Sixx and Nathan Followill are among those shocked and stunned by the Colorado cinema midnight massacre.
Gunman James Holmes, 24, walked into a packed Aurora cinema shortly after the beginning of the venue's first screening of blockbuster The Dark Knight Rises and opened fire, killing 12 film fans and injuring 59 others.
Celebrities across the world have taken to blogs and websites to comment on the killing spree and now Captain America Chris Evans, Motley Crue's Nikki Sixx and Kings of Leon star Nathan Followill have offered their thoughts.
Nathan Followill writes, "My thoughts & prayers go out to those affected... Such a senseless & cowardly act," while Nikki Sixx adds, "Breaks my heart hearing the news about the shooting's (sic) in Aurora, Colorado. My prayers and thoughts go out to the families and victims."
And actor Chris Evans is still trying to understand why someone would want to kill innocent people watching a movie: "what the hell is happening?? my heart is completely shattered. all of my thoughts and prayers are with the people of aurora."
Meanwhile, The Roots star Questlove takes aim at the parents of the baby caught up in the tragedy, tweeting, "Why was a 3 month old at a midnight premiere?"
Tributes to the victims have also been tweeted from Nicole 'Snooki' Polizzi, rockers Chris Daughtry and Hayley Williams, Janelle Monae, Russell Simmons and dance music star Moby, who asks, "what is wrong with us? too tragic and heartbreaking."