Video released early Monday by New Orleans police shows a possible suspect in the Mother's Day gunfire that wounded 19 people during a neighbourhood parade. 

The grainy surveillance video shows a crowd suddenly scattering in all directions, with some falling to the ground. They appear to be running from a man who turns and runs out of the picture. The person is wearing a white T-shirt and dark pants. The image isn't clear but police say they hope someone will recognize him and notify investigators.

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Shootings at parades and neighbourhood celebrations have become more common in recent years as New Orleans struggles with street crime. (Lauren McGaughy/Nola.com/The Times-Picayune)

Still pictures of the suspect have been posted on YouTube, police said. 

Police believe more than one gun was fired in the burst of Sunday afternoon violence — the latest to flare up around a New Orleans celebration this year — and they have vowed to swiftly track down those responsible.

Detectives were conducting interviews, collecting any surveillance video they could find and gathering evidence from the scene. Cellphone video taken in the aftermath of the shooting shows victims lying on the ground, blood on the pavement and others bending over to comfort them. 

Police also say the reward for information leading to arrests and indictments in the case is $10,000. 

The crime scene was about 2.4 kilometres from the heart of the French Quarter and near the Treme neighbourhood, which has been the centrepiece for the HBO TV series Treme

Sunday's violence comes at a time when the city is struggling to pay for tens of millions of dollars required under federal consent decrees to reform the police department and the city jail. 

Shootings at parades and neighbourhood celebrations have become more common in recent years as the city has struggled with street crime, sometimes gang-related. 

At least three victims of Sunday's shooting were seriously wounded. Of the rest, many were grazed and authorities said that, overall, most wounds were not life threatening. No deaths were reported. 

The victims included 10 men, seven women, a boy and a girl. The children, both 10 years old, were grazed and in good condition. 

'Strictly an act of street violence'

It's not the first time gunfire has shattered a festive mood in the city this year. Five people were wounded in January after a Martin Luther King Jr. Day parade, and four were wounded in a shooting in the French Quarter tourist district in the days leading up to Mardi Gras. 

"The specialness of the day doesn't appear to interrupt the relentless drumbeat of violence," Mayor Mitch Landrieu said at a news conference outside a hospital where victims were being treated Sunday night. 

Mary Beth Romig, a spokeswoman for the FBI in New Orleans, said federal investigators have no indication the shooting was an act of terrorism. 

"It's strictly an act of street violence in New Orleans," she said. 

As many as 400 people came out for the second-line procession — a boisterous New Orleans tradition — though only half that many were in the immediate vicinity of the shooting, Police Supt. Ronal Serpas said. Officers were interspersed with the marchers, which is routine for such events. 

Police saw three suspects running from the scene. No arrests had been made as of late Sunday. 

Second-line parades are loose processions in which people dance down the street, often following behind a brass band. They can be planned events or impromptu offshoots of other celebrations. They trace their origins to the city's famous jazz funerals. 

The neighbourhood where the shooting happened is a mix of low-income and middle-class row houses, some boarded up. As of last year, the 7th Ward's population was about 60 per cent of its pre-Hurricane Katrina level.