Published Tuesday, 13 May 2014
US celebrity website TMZ posted the minute-long video on Monday and said it was shot last week inside a lift at New York's Standard Hotel.
The Standard Hotel issued a statement saying it is "shocked and disappointed that there was a clear breach of our security system".
The video appears to show Solange attacking Jay Z in his wife Beyonce's presence. A security guard intervenes.
There is no audio during the video.
The hotel said the security leak violates the confidentiality it provides customers.
A statement read: "We are investigating with the utmost urgency the circumstances surrounding the situation and, as is our customary practice, will discipline and prosecute the individuals involved to our fullest capacity."
TMZ later posted a longer, three-minute version of the video.
The footage shows the performers in the outfits they wore to the Met Gala last week.
Representatives for Beyonce, Jay Z and Solange have so far declined to comment.
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