The New Orleans attack suspect, identified by the FBI as 42-year-old US citizen Shamsud-Din Jabbar, appeared to be a real estate agent from Texas who had spent 10 years as an IT specialist in his country's army.

In a video posted on YouTube four years ago, Jabbar – speaking with a southern US accent – boasted of his skills as a "fierce negotiator" as he advertised his property management services to potential clients.

Criminal records reported by the New York Times show that Jabbar had two previous charges for minor offences – one in 2002 for theft and another in 2005 for driving with an invalid licence.

Jabbar was twice-married, according to the newspaper, with his second marriage ending in divorce in 2022, when he detailed experiencing financial problems in an email to his wife's lawyer.

"I cannot afford the house payment," he reportedly wrote, adding that his real estate company had lost more than US$28,000 in the previous year, and that he had taken on thousands in credit card debt to pay for lawyers.

The Atlanta Journal-Constitution newspaper reported that Jabbar had gotten a degree from Georgia State University.

Jabbar said in his YouTube video that he served in the US military for a decade as a human resources specialist and an IT specialist.

He said that with this experience, he "learned the meaning of great service and what it means to be responsive and take everything seriously, dotting I's and crossing T's to make sure that things go off without a hitch."

The FBI confirmed at a news conference that Jabbar was a US army veteran but did not detail his role. The agency said it was believed that he had been honourably discharged, but that its probe was ongoing.

At least 15 people were killed and more than 30 wounded when Jabbar allegedly drove a truck at high speed into a crowd of New Year's revellers in New Orleans.

Authorities said he crashed the vehicle, then opened fire and was killed in a shootout with police. (AFP)