The surveillance video appears to show R&B singer Solange yelling at the rapper before wildly hitting and kicking him as a man who seems to be a security guard tries to restrain her. At one point, Beyoncé, 32, steps in to stand between her husband and sister.
Watch the full three-minute video of the fight between Jay Z, 44, and Solange, 27, below:
Beyoncé, Jay Z and Solange all attended the ball May 5 before heading to The Standard hotel in New York. The Knowles sisters didn't show any signs of strife at the gala, posing for an Instagram photo along with Sarah Paulson and Lupita Nyong'o.
Just a few weeks earlier, the three recording artists also spent time together at Coachella, and Solange even brought Beyoncé on stage during her set for a surprise dance performance.
Reps have not yet replied to requests for comment.