Jabbar, a resident of Texas who had served the US Army in Afghanistan, killed 15 people and injured 30 others ramming the truck into the revellers.

The man, who was shot by police soon after he rammed the vehicle into the crowd, is assumed to be not alone in carrying out the incident.

"The FBI is the lead investigative agency, and we are working with our partners to investigate this as an act of terrorism. We are aggressively running down all leads to identify any possible associates of the subject," the Federal Bureau of Investigation (FBI) said in a statement.

The FBI added, "The subject has been identified as 42-year-old Shamsud-Din Jabbar, a U.S. citizen from Texas. He was driving a Ford pickup truck, which appears to have been rented, and we are working to confirm how the subject came into possession of the vehicle."

Truck rams into crowd in New Orleans during New Year celebrations | Photo courtesy: Shanghai Eye X page video grab

"An ISIS flag was located in the vehicle, and the FBI is working to determine the subject's potential associations and affiliations with terrorist organizations."

"Weapons and a potential IED were located in the subject’s vehicle. Other potential IEDs were also located in the French Quarter. The FBI’s special agent bomb technicians are working with our law enforcement partners to determine if any of these devices are viable, and they will work to render those devices safe," the statement said.

Jabbar was in the regular Army from March 2007 to January 2015 and he then moved to the Army Reserve from January 2015 to July 2020, an Army spokesperson said as Reuters reported.

Condemning the incident, outgoing US president Joe Biden posted on X, "... My heart goes out to the victims and their families who were simply trying to celebrate the holiday. There is no justification for violence of any kind, and we will not tolerate any attack on any of our nation's communities."

Eyewitnesses recount horrifying incident

"All I saw was a truck slamming into everyone on the left side of Bourbon sidewalk," said Kevin Garcia, 22, speaking to CNN shortly after the incident.

"A body came flying at me," he said, adding that he also heard gunshots being fired.

Another witness, 22-year-old Whit Davis from Shreveport, Louisiana, told CNN the incident occurred while he was leaving a nightclub on Bourbon Street.

"Everyone started yelling and screaming and running to the back, and then we basically went into lockdown for a little bit and then it calmed down but they wouldn’t let us leave," Davis said.