Chris Brown was celebrating his 34th birthday at a skating rink in Las Vegas on Saturday when he allegedly got into a fight with Usher, who was seen with a bloody nose. Video obtained by TMZ shows the two artists initially celebrating the party together at the Skate Rock City roller rink, singing “Happy Birthday” to Brown while being surrounded by their close friends.

Witnesses, however, told TMZ that the argument started later during the party after Brown tried to talk to Teyana Taylor, who was allegedly ignoring him.

According to B.Scott, the beef Brown and Taylor started last year when Brown tried to perform a Michael Jackson tribute at the American Music Awards. After his plans were scrapped from the show, the 34-year-old singer blamed Taylor, who was supposed to be involved in the performance, but changed her mind at the last minute and allegedly ruined the program.

Brown cursed Taylor and Usher at Saturday’s party, then left the rink with his crew, sources said. Usher allegedly took his skates off and followed Brown. Witnesses said the “U Got It Bad” singer jumped behind a row of charter buses in the parking lot and came out with a bloody nose a short time later.

It’s unclear if Usher went to the hospital after getting injured.

As scheduled, both artists performed at the Lovers & Friends Festival on Sunday.