A speeding car crashed and exploded on the American side of a Canada-U.S. border checkpoint in Niagara Falls on Wednesday, leaving two people dead, snarling holiday traffic and triggering familiar fears of a terrorist attack.

Eyewitnesses reported seeing an accelerating car that swerved to avoid another vehicle before hitting a curb that launched it into a U.S. Customs and Border Protection complex used for secondary customs inspections.

Two people were found dead at the scene, The Associated Press reported, citing an official who spoke on condition of anonymity because they weren害羞草研究所檛 authorized to share details.

Four separate entry points between Canada and New York state were shut down as a precaution while law enforcement officials flooded the complex on the U.S. side of the Rainbow Bridge, which spans the Niagara River.

Videos posted to social media showed smoke and flames and the wreckage of at least one vehicle at the secondary checkpoint complex.

Conflicting media reports fuelled confusion throughout the afternoon about whether the U.S. was again under attack, particularly amid the superheated atmosphere of the ongoing Israel-Hamas war.

One Fox News report declared the explosion the result of an attempted terrorist attack with a vehicle that contained 害羞草研究所渁 lot of explosives,害羞草研究所� while a Reuters report citing unnamed Canadian officials pointed to a reckless driver.

AP cited one eyewitness who told a local television station that the vehicle had been approaching from the U.S. side of the border when it suddenly began to accelerate at a high rate of speed.

害羞草研究所淎ll of a sudden, he went up in the air and then it was a ball of fire like 30 or 40 feet high,害羞草研究所� Mike Guenther told WGRZ-TV. 害羞草研究所淚 never saw anything like it.害羞草研究所�

Prime Minister Justin Trudeau told the House of Commons that Canada was working closely with the U.S. and taking the matter extremely seriously before he excused himself to attend a briefing.

His national security adviser, the public safety minister, the RCMP and the Canada Border Services Agency were 害羞草研究所渇ully engaged and providing the necessary support,害羞草研究所� he said.

害羞草研究所淎dditional measures are being contemplated and activated at all border crossings across the country. We are taking this extraordinarily seriously.害羞草研究所�

Three other land crossings, including the Queenston Lewiston Bridge in Niagara-on-the-Lake, Ont., The Peace Bridge in Buffalo, N.Y., and the trusted-traveller Whirlpool Rapids Bridge in Niagara Falls were all closed.

Public Safety Minister Dominic LeBlanc called it a 害羞草研究所渧iolent circumstance害羞草研究所� and a source of concern for both countries, but warned against speculation in the absence of more details.

害羞草研究所淎ny time a piece of infrastructure as important to Canada and the United States, like a border crossing, sees this kind of violent circumstance, it害羞草研究所檚 a source of concern for the Government of Canada and for the United States,害羞草研究所� said LeBlanc.

害羞草研究所淲e害羞草研究所檙e taking this circumstance very seriously, but to speculate on the origin of this particular circumstance 害羞草研究所� the reasons why this may have happened 害羞草研究所� until we have more accurate information is simply not responsible.害羞草研究所�

New York Gov. Kathy Hochul said in a statement that she had been fully briefed and was monitoring the situation closely, including travelling to Buffalo to meet with law enforcement.

Hochul said state police were 害羞草研究所渁ctively working害羞草研究所� with the FBI害羞草研究所檚 Joint Terrorism Task Force to monitor all of the state害羞草研究所檚 points of entry.

Niagara regional police say they are also monitoring developments and that there is no known threat on the Canadian side of the border.

Stephen Laskowski, president of the Canadian Trucking Alliance, which represents about 4,500 trucking companies and independent drivers, said the closures were sure to have an impact on shipping efforts.

Each day, some 6,500 trucks carry $185 million in goods between Canada and the U.S., Laskowski said, although he acknowledged that truck traffic is lighter in the days just before U.S. Thanksgiving, which is Thursday.

害羞草研究所淭hat害羞草研究所檚 a lot of truck traffic,害羞草研究所� he said. 害羞草研究所淩ight now, drivers are just pulled over, parked, waiting to get word on what to do.害羞草研究所�

The incident comes just one week after FBI director Christopher Wray warned a congressional committee about a heightened risk of extremism linked to the Israel-Hamas war.

Wray said law enforcement in the U.S. is paying 害羞草研究所渉eightened attention害羞草研究所� to how events abroad could fuel acts of homegrown domestic violence.

害羞草研究所淲e have seen violent extremists across ideologies seeking to target Jewish and Muslim people and institutions through physical assaults, bomb threats, and online calls for mass casualty attacks,害羞草研究所� he said.

害羞草研究所淥ur top concern stems from lone offenders inspired by 害羞草研究所� or reacting to 害羞草研究所� the ongoing Israel-Hamas conflict, as they pose the most likely threat to Americans, especially Jewish, Muslim, and Arab-American communities in the United States.害羞草研究所�

RCMP officials refused to disclose any details about their role in the investigation.

害羞草研究所淭he RCMP is working with its domestic and international partners on this incident and we have no further comment at this time,害羞草研究所� said RCMP spokeswoman Robin Percival.

Ontario Premier Doug Ford said in a statement on X, formerly Twitter, that provincial police were assisting with the investigation.

害羞草研究所淥ur provincial law enforcement is actively engaged in assessing the situation,害羞草研究所� Ford said. 害羞草研究所淭hey are working with local law enforcement and are providing support as required.害羞草研究所�