An argument escalated into a concert-clearing brawl at the Middle East nightclub Friday night, resulting in the arrest of a Boston man after he stabbed two people.

The incident began around 11 p.m. with a dispute between Paul Solet, 21, of Boston, and a New York man attending a hip-hop concert in the basement of the popular Central Square club.

The cause of the fight is unclear, but a witness said that after the two had argued for a few minutes he saw the New York man bleeding from his forehead. The witness then approached Solet and saw a knife in his right hand.

Security guards tried to stop the fight but friends of the victim, who is black, and friends of Solet, who is white, then began to fight.

"[The assailant] started bugging out and my people tried to stop him and then his people got into it," said one witness who was injured during the fight.

"They just couldn't stop the fight," said Michael Entelman, a concert reviewer for The Boston Phoenix who was attending the show. "They kicked some guys out and then some other people started fighting."

Cambridge resident Michael Moses was standing outside the club when people started coming out after the fight.

"We were coming in the door when about five or six guys came out, one with a gash over his eye," said Moses. "They said a white guy had a razor and was cutting people up."