Video released this morning by New Orleans police shows a possible suspect for the Mother's Day gunfire that wounded 19 people yesterday 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 man is wearing a white T-shirt and dark trousers.

The image is not clear, but police say they hope someone will recognise him and notify investigators.

Police believe more than one gun was fired in the shooting and 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.

Mobile phone 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 say the reward for information leading to arrests and indictments in the case is $10,000. (€7,700)

The crime scene was about 2.4km from the heart of the French Quarter and near the Treme neighbourhood.

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 yesterday’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 ten men, seven women, a boy and a girl. The children, both aged ten, were grazed and are in good condition.

Earlier this year, five people were wounded in January after a Martin Luther King Jr Day parade in the city, 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 last 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 New Orleans tradition - though only half that many were in the immediate vicinity of the shooting, Police Superintendent 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 last night.

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.