Hours later federal and state authorities said investigators had found no evidence of an act of terror, though circumstances surrounding the episode on the Rainbow Bridge remained murky, leaving it yet to be determined whether the crash was accidental or intentional.
"At this time, there is no indication of a terrorist attack," New York Governor Kathy Hochul told reporters Wednesday evening. Her comments were echoed a short time later by federal law enforcement officials at a separate news conference.
The explosion is under investigation by agents from the FBI field office in Buffalo, New York.
Video of the crash caught on security camera and posted to X by the US Customs and Border Protection (CBP) agency showed the car travelling at high speed, then hitting an object and flying into the air before it crashed to the ground and exploded in flames.
The driver and a passenger perished in the wreck, and a CBP officer suffered minor injuries. He was treated at a nearby hospital and released, an agency official said later.
Authorities did not give names of the two people believed to have been killed. CNN reported the driver was a 56-year-old man who had been on his way to a rock concert in a luxury Bentley car with his wife.
The incident unfolded at a time of heightened security concerns around the world stemming from the conflict in the Middle East and at the peak of US holiday travel on the eve of Thanksgiving celebrations.
Buffalo International Airport, about 30km south of crash scene, was closed to all departing and arriving international flights following the incident, the Federal Aviation Administration said on its website.
The Rainbow Bridge and all three other border crossings along the Niagara River between western New York and southern Ontario - the Peace Bridge, the Lewiston-Queenston Bridge and the Whirlpool Bridge - were shut down for several hours afterward as precaution.
Other international crossings remained open on "heightened alert status," according to the governor.
Security measures also were escalated at other airports and railways managed by the Niagara-Frontier Transit Authority, as well as at various locations around New York City, officials said.
The three bridges that were not involved were reopened early on Wednesday evening, but the Rainbow crossing remained closed during the continuing investigation of the scene and as officials assessed the crossing's safety.
CBP is working closely with — CBP (@CBP) @FBI, federal, state & local partners in response to a vehicle explosion at Rainbow Bridge which remains closed. Out of abundance of caution, CBP temporarily suspended inbound/outbound traffic at 3 other Buffalo crossings that have since reopened. pic.twitter.com/pTXyUsavRBNovember 22, 2023
Hochul said the car that crashed sailed over a 2.5m fence before landing in a fireball that incinerated the vehicle, leaving little but the engine visibly intact and scattering debris over more than a dozen security booths on the bridge.
Eyewitness Mike Guenther told Buffalo television station WGRZ-TV that he was walking near the bridge with his wife when the car travelling from the US side at high speed, struck a fence at the crossing and was catapulted into the air before exploding.
"He was flying, over 100 miles an hour," said Guenther, who was visiting from Kitchener, Ontario, adding the vehicle was "fish-tailing" out of control before it crashed.
"It was a ball of fire, 30 or 40 feet high, never seen anything like it," Guenther said. He described the car as a luxury sedan.
