Updated

The FBI is investigating a vehicle explosion that occurred Wednesday at the Rainbow Bridge border crossing between the U.S. and Canada.

The vehicle was heading from the U.S. to Canada and was going in the direction of the border officer building, sources told Fox News' Alexis McAdams.

All bridges were closed in the area, and all government buildings were evacuated, according to sources. Sources tell Fox News' Alexis McAdams that the incident was being treated as a possible attack.

Fox News' Alexis McAdams was told by sources that the explosion was so big and fierce, that authorities first thought it was a terrorist attack.

New York Governor Kathy Hochul said the incident happened at 11:27 a.m. when someone driving a car crashed into a median at the border crossing. She added that there's "no sign" that the incident was a terrorist attack, adding that a "local individual" was involved and both people inside the car died.

"There is no evidence at this time that this was a terrorist activity. And that's what I want to make very clear to the public," she Hochul said.

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Law enforcement on the scene of an explosion at Rainbow bridge

FBI probe vehicle explosion at US-Canada bridge near Niagara Falls. (Reuters)

General view of police activity on the Rainbow Bridge following an explosion

General view of police activity on the Rainbow Bridge between the US and Canada following an explosion today, Wednesday, November 22, 2023. (Rob Bennett)

International border crossing points between Canada and Western New York were closed after the reported incident, which has also injured at least one person, a 27-year-old male who was taken to Niagara Falls Memorial Hospital with minor injuries, including back pain and minor cuts. His condition is not severe.

"The FBI Buffalo Field Office is investigating a vehicle explosion at the Rainbow Bridge, a border crossing between the US and Canada in Niagara Falls," the FBI said in a statement.

Surveillance video released by U.S. Customs and Border Patrol shows a car going airborne before exploding.

CBP Field Director Rose Brophy said at a press conference that one officer from the agency taken to a local hospital for minor injuries but was later released.

FBI Special Agent-in-Charge Matthew Miraglia said they have a "subject in mind" regarding who was driving the car and said there's no further threat to the area.

U.S. Attorney Trini E. Ross said the FBI's initial assessment is that the incident wasn't terrorism-related.

"We will continue to investigate, but our preliminary assessment of the situation is that it was not terrorism-related," Ross said.

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Rainbow Bridge border crossing vehicle explosion scene

The FBI said it is investigating a vehicle explosion Wednesday, Nov. 22, 2023, at the Rainbow Bridge border crossing between the U.S. and Canada. (Fox News)

General view of police activity on the Rainbow Bridge following an explosion

General view of police activity on the Rainbow Bridge between the US and Canada following an explosion today, Wednesday, November 22, 2023. (Rob Bennett)

It continued, "The FBI is coordinating with our local, state, and federal law enforcement partners in this investigation. As this situation is very fluid, that's all we can say at this time."

Rainbow Bridge connects Niagara Falls, New York with Niagara Falls, Canada.

New York Governor Kathy Hochul said in a statement that she's traveling to Buffalo.

"I have been briefed on the situation that occurred at the Rainbow Bridge in Niagara Falls," Hochul said. "At my direction, the New York State Police is actively working with the FBI Joint Terrorism Task Force to monitor all points of entry to New York. I am traveling to Buffalo to meet with law enforcement and emergency responders and will update New Yorkers when more information becomes available."

WATCH: Vehicle explosion at US-Canada border crossing

In a statement posted to X, FBI Buffalo said it has completed its investigation.

"FBI Buffalo has concluded our investigation at the scene of the Rainbow Bridge incident. A search of the scene revealed no
explosive materials, and no terrorism nexus was identified. The matter has been turned over to the Niagara Falls Police
Department as a traffic investigation," the agency said. "The FBI thanks our local, state, and federal law enforcement partners for their assistance, and we remain committed in our mission to keeping the public safe."

New York City Mayor Eric Adams said that the NYPD has enhanced security.

"The NYPD and our team have been closely monitoring the situation on the ground in Buffalo after an explosion at the Rainbow Bridge, and we’ve already sent NYPD officers upstate to support efforts on the ground. The NYPD and our partners have already enhanced security, and the city is on heightened alert due to the upcoming holiday, so the public will see increased security at locations across New York City, including entry and egress points into and out of the city," Adams said.

Map shows Rainbow Bridge vehicle explosion

A map shows the location of the Rainbow Bridge vehicle explosion at the U.S.-Canada border crossing, which happened Wednesday, Nov. 22, 2023. (Fox News)

Peace Bridge, Lewiston-Queenston Bridge, and Whirlpool Bridge were closed as the incident was investigated.

Buffalo Airport said in a statement that travelers can expect additional security measures. The FAA later announced that Buffalo International Airport was closed to all arriving and departing international flights.

"In response to the incident that is unfolding at the Rainbow Bridge, the NFTA is increasing security system-wide. Cars coming into the Buffalo Airport will undergo security checks and travelers can expect additional screenings. The Buffalo and Niagara Falls Airports are fully operational. We advise travelers to give themselves time for these extra precautions in addition to holiday travel," the airport said.

Sen. Chuck Schumer, D-N.Y., said in a statement that he's closely monitoring the situation in Buffalo.

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General view of police activity on the Rainbow Bridge following an explosion

General view of police activity on the Rainbow Bridge between the US and Canada following an explosion today, Wednesday, November 22, 2023. (Rob Bennett)

"I’m closely monitoring the situation on the Rainbow Bridge crossing between the US & Canada in Niagara Falls Federal, state, & local law enforcement officials are on the ground and investigating Follow guidance from emergency officials Thank you to our brave first responders," he said.

"Because of the situation on the Rainbow Bridge between the US and Canada in Niagara Falls, both the Rainbow Bridge and the Peace Bridge are now closed. Please avoid the area and follow the guidance of law enforcement and first responders," Sen. Kirsten Gillibrand wrote in a post on X. 

Fox News' Jeremy Copas and Mark Meredith contributed to this report.