Gunfire injures 9 on Bourbon Street

• NEW: Police believe two young men are responsible for the shooting


• NEW: Police say some victims in the tourist-area shooting are not from New Orleans


• A total of nine people were shot during the incident


• Two people are in critical condition after late-night shooting in French Quarter

(CNN) -- Gunfire struck nine people on Bourbon Street in New Orleans early Sunday, police spokesman Frank Robertson said.

The shooting happened at 2:45 a.m. in the French Quarter. Initial reports had indicated that seven people were injured in the incident.

Superintendent of the New Orleans Police Department Ronal Serpas said Sunday that the shooting may have occurred due to a heated exchange between two young men.

"Right now, we believe they did exchange gunfire," he said at a press conference. "Those two young men choose to hurt each other and put other people at risk."

Gunfire injures several in New Orleans

Police Chief: I hope they are listening

The victims were taken to two different hospitals in the area. Two of the victims are in critical condition, Serpas said. The other seven are in stable condition and suffered non-life-threatening injuries, Robertson said.

Additional information on the victims has not been released so far, but Serpas said some of them were not from New Orleans.

Investigators are reviewing evidence and surveillance video, but have not established a motive for the shooting. Police are urging neighboring businesses and any eyewitnesses to turn in video or evidence that might help them catch those responsible for the shooting, according to Serpas.

"This is a heinous crime. These are two young men, both armed with firearms, who chose to settle a dispute between themselves without a moment's care for anyone else," Serpas said. "I hope that they are listening. I hope that their friends are listening. I hope their moms and them are listening."

The 700 block, where the shooting occurred, is a popular gathering place for tourists and revelers, where many of them pack bars and clubs between St. Peter and St. Ann Streets. Crowds often spill into the streets.

The scene is around the corner from other famed attractions, such as jazz concert venue Preservation Hall and the popular bar Pat O'Brien's.

CNN's Carma Hassan and Patrick Cornell contributed to this story.