Mia Farrow, Octavia Spencer and boxer Mike Tyson have expressed their horror after a gunman opened fire at a Sikh temple in Wisconsin, killing six people.
Police reveal the shooter opened fire at the gurdwara at around 10.30am local time in the town of Oak Creek, near Milwaukee.
Four people were found dead inside the temple, while two more lives were claimed outside the building.
The gunman's body was also among the dead after he was shot by a veteran cop.
The officer was one of three critically injured in the incident.
Initial reports suggested there may have been more than one attacker, but police chief Bradley Wentlandt has confirmed that no other suspects have been found.
The killer's identity had yet to be released as WENN went to press.
Actress and humanitarian Farrow was one of the first celebrities to comment on the latest gun tragedy, taking to Twitter.com to write, "Thoughts and prayers are with the people of the Oak Creek Sikh Temple in Wisconsin".
The Help star Spencer tweets, "Another shooting, what is going on in this country? why do the crazies decide that innocent people should suffer their madness?! WeAllLose", while Tyson adds, "Prayers with the victims and their families in the Wisconsin Sikh Temple".
Singer Josh Groban writes, "Horrible news from Wisconsin..my heart goes out to the Sikh community" and Sara Bareilles posts, "More violence in the news. So so sad. My heart is heavy and my prayers are for peace. Peace. Love. Peace".
The Wisconsin shooting comes just over two weeks after 12 film fans were killed and 58 others injured during a Colorado cinema massacre.
Suspect James Holmes has been charged with 142 counts, including first-degree murder, for the tragedy, which occurred as victims sat down for a midnight screening of The Dark Knight Rises in an Aurora theatre on 20 July (12).