NEW YORK (AFP) - A New York hotel said Thursday it has fired an employee over a leaked elevator video showing rapper Jay-Z being attacked by sister-in-law Solange Knowles as wife Beyonce looked on.

In a statement that did not name names, The Standard said it had identified the person responsible for breaching its security policies "and recording the confidential video."

"The Standard has already terminated the individual and will now be pursuing all available civil and criminal remedies," it said, adding that it would turn over "all available information" to police.

The fuzzy, silent black-and-white video posted on TMZ.com shows Knowles kicking and hitting Jay-Z in the elevator at The Standard hotel, site of an after-party following the glamorous Met Gala in New York on May 5.

A bodyguard is seen trying to restrain the clearly agitated 27-year-old singer, whose 32-year-old megastar sister Beyonce stood largely in the corner alongside her 44-year-old husband of six years.

It's not clear what provoked the incident.

But the trio can be recognised by the outfits they wore earlier that night at the Metropolitan Museum fashion gala - Solange in a pink Phillip Lim dress, Beyonce in a sheer black Givenchy Haute Couture gown and Jay-Z in a white tuxedo jacket.

Solange, whose new album is due out later this year, performed at the Coachella music festival in California last month, where Beyonce joined her on stage, delighting fans.

The Met Gala after-party took place at The Standard's exclusive rooftop lounge - better known among New York night owls as "the Boom Boom Room".