On Monday, the Department of Homeland Security and the FBI issued a joint statement warning of the potential for copycat “vehicle ramming” attacks, similar to the one carried out by Islamic terrorist Shamsud-Din Jabbar, who killed 14 people and injured dozens more in New Orleans on New Year’s Day.

The statement emphasized that attackers both in the U.S. and abroad have utilized rented vehicles, which are “easy to acquire,” and also warned of the possibility of terrorists using other weapons such as guns, knives, and explosives. The DHS and FBI urged the public to remain vigilant and report any suspicious activity to law enforcement, The Hill reported.

“The FBI and DHS are concerned about possible copycat or retaliatory attacks due to the persistent appeal of vehicle ramming as a tactic for aspiring violent extremist attackers. Previous attackers inspired by foreign terrorist organizations (FTOs) who have conducted vehicle attacks in the United States and abroad have used rented, stolen, and personally owned vehicles, which are easy to acquire,” the agencies wrote.

“Some have used additional weapons, such as firearms and knives, to attack individuals after the vehicle has stopped. Additionally, attackers may attempt to conceal and pre-position improvised explosive devices (IEDs) to supplement a vehicle attack,” they added.

Recently released bodycam footage shows Shamsud-Din Jabbar, a 42-year-old Army veteran from Texas who had recently pledged allegiance to ISIS, firing on police after crashing his truck on Bourbon Street. Just an hour before the attack, Jabbar had placed IEDs along Bourbon Street, though the explosives did not detonate. Jabbar was shot and killed by New Orleans police officers who returned fire.

Police discovered a transmitter for detonating the IEDs in his rented truck, along with an ISIS flag.

Officials are continuing to investigate the security measures in place to protect those celebrating the New Year on Bourbon Street.

Despite having portable steel barriers typically used to block off streets during large events, the city did not deploy any steel barriers to secure Bourbon Street during the New Year’s Day celebration. Jabbar was able to access the busy street by driving past a police car that was parked to block it off.

In a “60 Minutes” interview on Sunday, outgoing FBI Director Christopher Wray said that terrorists like Jabbar “radicalize not in years but in weeks,” adding that their “method of attack is still very deadly but fairly crude.”

“The investigation’s very much ongoing. But what I can say right now is that he appears to have been inspired — from afar — by ISIS. And it is, in many ways — the most challenging type of terrorist threat we face,” Wray added.