Nicki Minaj and R&B singer Jay Sean were among the stars left stunned after a gunman opened fire outside New York City's Empire State Building on Friday morning (24Aug12) .
Suspected gunman Jeffrey Johnson opened fire on a crowd of people outside the landmark, killing his former boss at women's accessories firm Hazan Imports, who fired the 53 year old last year (11).
Nine bystanders were wounded during the shootout before police officers shot Johnson dead.
The victims are currently receiving treatment, with four listed in serious condition.
As news of the tragedy emerged, several celebrities took to Twitter.com to express their horror and send condolences to all those affected by the tragedy.
In a post, Minaj wrote, "Sorry to hear about this New York shooting. Sending love to the families and friends of the victims," and Jay Sean added, "Shootin near empire state building this morning - crazy. Hope any of u who might've been nearby are ok seein as its (a) major tourist area (sic). Crazy".
Music mogul Russell Simmons also offered his thoughts to those recovering from their wounds, writing, "Prayers to the victims of the Empire State Building shooting".
And pop star Joe Jonas tweeted, "My heart goes out to everyone involved at the empire state building you are in our prays (prayers)".