According to video obtained by TMZ, Beyoncé's sister Solange attacked Jay Z in an elevator at an after-party for last week's Met Gala.

TMZ's sources said the attack took place at the Standard Hotel, just after the Gala ended.

It's unclear what prompted the attack, but in the video you can see Solange approach Jay Z—yelling, according to TMZ—before shoving, pushing, and then kicking him as he stands next to Beyoncé. At one point, another man in the elevator, possibly a bodyguard, tries to hold her back but she still gets off one more kick, which a very calm Jay Z catches.

TMZ also notes that the man hits a button in the elevator—possibly to prevent the elevator from opening mid-fight in front of the party.

UPDATE: Here's the full video.