One person was injured at Potawatomi Bingo Casino, a Milwaukee casino at about 1:30 a.m. Sunday as a man opened fire on his girlfriend, the Milwaukee Sentinel reported. A 27-year-old man allegedly fired a handgun, wounding the 23-year-old woman, sending gamblers to flee.

Cheryl Anderson of Milwaukee told The Associated Press she was at the slot machines when she heard a shot, which she said was fired at the nearby table games.

"We all of a sudden heard a bang," Anderson said. "... It was a shooting, you could tell. It was so loud like a cannonball. We hit the floor, everybody was panicking. We just stayed there because we didn't know what the heck to do. We saw a guard running, everybody running."

Police told WISN Channel 2 that the woman and her boyfriend got into an argument and he shot her.

Multiple people told the Journal Sentinel that frightened patrons stampeded in two waves toward the casino's exits, news reports said. The casino temporarily closed after the shooting. The woman was taken to a local hospital, with non-life-threatening injuries, police said. The casino reopened at 9 a.m.

"I just heard people running and shouting 'somebody is shooting. Somebody is shooting.' And it was like what what. Then everybody got off of the machines and were running," says Patricia Wesley.

"We are thankful no one was hurt more seriously and that the situation was contained quickly," the casino said in a written statement.

Charges are still pending, and the case will be referred to the Milwaukee County District Attorney's Office.