WASHINGTON – A vehicle exploded on Nov 22 on the Rainbow Bridge linking Canada with the United States at Niagara Falls, prompting the authorities to close that border crossing and the three others between western New York and southern Ontario, officials said.

The vehicle’s driver and a passenger were killed in the explosion, and one US Customs and Border Protection (CBP) officer was injured, a person with knowledge of the situation told Reuters.

Investigators ruled out a bomb as the cause, but the possibility of terrorism had yet to be discounted because the circumstances of the incident remained undetermined, according to the source, who asked to remain anonymous in order to discuss the matter.

“It’s not being ruled out because we really have no idea what happened,” said the source.

US Senate Majority Leader Charles Schumer said that according to a Federal Bureau of Investigation (FBI) briefing he received, “initial reports indicate the two people were killed in the car, but nothing’s been determined on their identity or motive”.

According to New York Governor Kathy Hochul, the FBI Joint Terrorism Task Force was mobilised to investigate the incident.

Initial indications from the CBP were that the incident was caused by a reckless driver whose actions resulted in a crash and fire, two sources familiar with the matter told Reuters.

While CBP officials were not ruling out a deliberate attack, preliminary evidence did not suggest that, they said.

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.

The US Federal Aviation Administration said on its website following the incident that Buffalo International Airport was closed to all departing and arriving international flights.

The Niagara Falls Memorial Medical Centre said it evaluated and treated a single patient with non-life-threatening injuries related to the incident. That patient had been discharged, the hospital said.

Fiery crash reported

Eyewitness and law enforcement accounts reported by other news media described a car speeding onto the bridge and careening out of control before crashing and bursting into flames.

The Niagara Gazette newspaper, citing law enforcement sources, said the car sped onto the bridge plaza, went through a fence separating the inbound lanes from the outbound lanes and towards the inspection lanes, where it exploded.

CNN, citing an unnamed source and showing video from the scene, reported that the vehicle approached from the US side of the border, accelerated, hit a curb and went airborne before catching fire and exploding.

Eyewitness Mike Guenther told a 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 Mr Guenther, who was visiting from Kitchener, Ontario, adding that the vehicle was “fishtailing” out of control before it crashed.

“It was a ball of fire, 30 or 40 feet high, never seen anything like it,” Mr Guenther said. He described the car as a luxury sedan.

The New York governor’s office said that 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 indefinitely as a precaution,

Other international crossings remained open on “heightened alert status”, according to the governor.

Three of the bridges closed after the incident carry vehicles only across the Niagara River between Ontario and New York, and are among the busiest border crossings in the world. The Whirlpool Bridge carries railroad traffic and vehicles.

Security measures were escalated at airports and railways in the region managed by the Niagara-Frontier Transit Authority, the governor’s office said.

New York City Mayor Eric Adams said in a statement that security also was tightened at various locations around the city.

Canadian Public Safety Minister Dominic LeBlanc told reporters in Ottawa: “This is obviously a very serious situation. The government of Canada is taking this situation extremely seriously.”

He added: “We are in close contact with the American authorities. I will be speaking with the US Homeland Security Secretary shortly.”

The FBI said in a statement on social media platform X, formerly twitter, that the explosion was under investigation by agents from the agency’s field office in Buffalo, New York.

“The FBI is coordinating with our local, state and federal law enforcement partners in this investigation,” the FBI statement said. “As this situation is very fluid, that’s all we can say at this time.”

New York Governor Hochul issued a separate statement on X saying that the New York State Police, at her direction, were “actively working with the FBI Joint Terrorism Task Force to monitor all points of entry to New York”.

Ontario Premier Doug Ford said in a post on X that law enforcement teams in Canada were “actively engaged in assessing the situation”.

Border agency officials in the United States had no immediate comment, while their Canadian counterparts did not immediately respond to a request for comment.

Representatives for the US State Department also did not immediately respond to a request for comment on the reported border closures.

The White House was closely monitoring the situation, as well, a spokesperson said. REUTERS