NEW ORLEANS >> Gunfire wounded four people on New Orleans’ famed Bourbon Street on Saturday night as a costumed crowd partied amid the countdown to Mardi Gras, sending people running, according to police and bystander accounts.

In a video taken by a witness and released by police  Sunday, four shots ring out rapidly, followed by screams as some in the crowd stagger into one another and a nearby wall. Police said in an email that an argument involving one of the victims led to the shooting. They described the video as showing two men leaving the argument and returning with a third, then approaching the victim and shooting. A man whom police identified in a statement as one of the perpetrators moves deeper into the crowd and extends his arm as the gunfire erupts.

No arrests were immediately reported, and police said they were seeking three men who fled, including the one seen extending his arm.

The wounded were two males and two females, New Orleans Police spokesman Frank B. Robertson said. One male victim was in guarded condition Sunday with shots to the abdomen, thigh and pelvis, Robertson said. The second male was shot in the buttocks, one female was shot on the chin and right foot, and the second female was shot on the toe, according to Robertson’s statement.

Police had said late Saturday that the most severely wounded man was undergoing surgery while the others were stable. None was identified by age or name.

The shooting came on the last weekend of partying before Mardi Gras, the Fat Tuesday celebration that is the signature tourist event of the year in New Orleans. And for thousands, the partying continued despite the shooting.

New Orleans has been plagued for years by violent crime, including gun violence that has soared since Hurricane Katrina devastated the city in 2005.

In 2011, sixteen people were shot and at least two killed in Halloween shootings in New Orleans. One of those killed — a 25-year-old local resident — was shot near the famous Chris Owens nightclub, about a block away from Saturday’s incident.

Police placed the Saturday shooting in the 400 block of Bourbon Street.

Patrick Clay, 21, a Louisiana State University student, told The Times-Picayune that he was standing on the corner of Bourbon Street on Saturday night when suddenly he saw a crowd running and people screaming that there had been a shooting.

"Everyone immediately started running and the cops immediately started running toward where people were running from," Clay said. "I was with a group of about seven people and at that point, we all just kind of grasped hands and made our way through the crowd as soon as possible."

Some bartenders and revelers said the block of Bourbon Street where the shooting occurred was closed for a time while detectives investigated, but partying resumed hours later across that stretch.

Julia Rosenthal, a 19-year-old from Westchester, N.Y., had mixed feelings about hanging out in the French Quarter after the shooting. "It’s not an OK thing that happened, and it’s definitely scary. But I’m not going to let it affect my night," she said.

Peter Manabani, an employee at the Rat’s Hole bar, said police had shut down a whole Bourbon Street block for an hour to investigate but allowed people to return to the area later.

Hours later, there was little evidence that a shooting had occurred. Overnight revelers were in full party mode, packing the block amid a heavy police presence.

Laura Gonzalez, 21, of Baytown, Texas, said it was her first Mardi Gras and she spent some time in the Fat Catz bar nearby as police investigated. She said the bar locked its doors quickly after the shots rang out and wouldn’t let anyone in or out while police went to the scene.

Asked if it was frightening, she responded: "Not really. We were just locked in a bar and we weren’t going to let this one incident wreck our party."

Parades rolled all day Saturday but none on Bourbon Street because the streets are too narrow. One of the biggest Mardi Gras parades, the Krewe of Endymion, rolled down a major thoroughfare and just skirted Bourbon Street a few hours before the shooting. Typically, once the parades end, partygoers head to the French Quarter.